Head & Neck — MCQs

Q: Impaired gag reflex is seen due to a lesion in which cranial nerves?

CN IX & X. ***Correct: CN IX & X*** The **gag reflex (pharyngeal reflex)** is a protective reflex involving two cranial nerves: - **Afferent limb**: **CN IX (Glossopharyngeal nerve)** provides sensory innervation to the posterior third of the tongue, oropharynx, and pharyngeal walls - **Efferent limb**: **CN X (Vagus nerve)** provides motor innervation to the pharyngeal muscles (via the pharyngeal plexus) that contract during the reflex **Clinical correlation**: Testing the gag reflex helps assess brainstem function and the integrity of CN IX and X. Impairment suggests lesions affecting these nerves or their nuclei in the medulla. *Incorrect: CN V & VI* - CN V (Trigeminal) provides facial sensation and motor to muscles of mastication, not involved in gag reflex - CN VI (Abducens) controls lateral rectus muscle for eye abduction *Incorrect: CN X & XI* - While CN X is involved, CN XI (Accessory nerve) innervates sternocleidomastoid and trapezius muscles, not pharyngeal muscles *Incorrect: CN VII & VIII* - CN VII (Facial) controls facial expression and taste from anterior 2/3 of tongue - CN VIII (Vestibulocochlear) is involved in hearing and balance, not the gag reflex *Incorrect: CN XI & XII* - CN XI (Accessory) innervates SCM and trapezius - CN XII (Hypoglossal) provides motor to intrinsic and extrinsic tongue muscles, not pharyngeal muscles involved in gag reflex

Q: Which tongue papillae do not have taste buds?

Filiform. ***Filiform*** - **Filiform papillae** are the most abundant type of papillae on the tongue and are responsible for the **mechanical action of gripping food**, due to their cone-shaped, abrasive structure of keratinized epithelium. - Unlike other papillae, they **lack taste buds** and thus do not play a role in taste sensation. *Fungiform* - **Fungiform papillae** are mushroom-shaped and are scattered among the filiform papillae, primarily on the tip and sides of the tongue. - These papillae **contain taste buds** on their superior surface and are involved in sensing taste stimuli. *Circumvallate* - **Circumvallate papillae** are large, dome-shaped structures arranged in a V-shape at the back of the tongue. - They are surrounded by a trench into which salivary glands empty, and their walls contain a **large number of taste buds**. *Foliate* - **Foliate papillae** are leaf-like folds located on the lateral margins of the posterior tongue. - They are **well-developed in young children** and contain taste buds, though they tend to degenerate with age. *Conical* - **Conical** is not a recognized classification of tongue papillae. While filiform papillae have a conical (cone-shaped) structure, "conical papillae" is not an anatomical term used to describe a distinct type of papilla.

Q: The nerve passing through the arrow-marked region in the provided image has been lesioned. Which of the following is the most likely clinical presentation?

Loss of sensation in the maxillary area of the face. ***Loss of sensation in the maxillary area of the face*** - The arrow points to the **foramen rotundum**, which transmits the **maxillary nerve (V2)**, a branch of the trigeminal nerve. - Lesion of the maxillary nerve (V2) leads to sensory loss in the **maxillary region of the face**, including the cheek, upper lip, upper teeth, and palate. *Loss of sensation in the jaw area* - Sensation in the jaw area, including the lower teeth and chin, is primarily supplied by the **mandibular nerve (V3)**, which exits through the foramen ovale. - A lesion at the foramen rotundum would not directly affect V3. *Loss of sensation on the scalp and nose* - Sensation to the scalp (anterior part) and nose is primarily supplied by the **ophthalmic nerve (V1)**, which exits the skull through the superior orbital fissure. - The foramen rotundum is not involved in the passage of the ophthalmic nerve. *Loss of sensation in the mucosa of nasopharynx* - While parts of the nasopharynx mucosa receive innervation from V2, this is a very specific and limited area, and the primary and most prominent sensory loss from a V2 lesion would be in the **maxillary facial region**. - Other nerves like the glossopharyngeal nerve also contribute to nasopharyngeal sensation. *Loss of motor function to muscles of facial expression* - Motor function to muscles of facial expression is supplied by the **facial nerve (CN VII)**, not the maxillary nerve (V2). - The maxillary nerve is a purely **sensory** branch of the trigeminal nerve and has no motor function. - The facial nerve exits the skull through the stylomastoid foramen, not the foramen rotundum.

Q: A patient was admitted with skull base trauma. The doctor was testing the marked structure in the pharyngeal region. Which of the following nerves was being tested?

Glossopharyngeal nerve. ***Glossopharyngeal nerve*** - The image shows a probe stimulating the posterior part of the **pharynx**, which elicits the **gag reflex**. - The afferent limb of the **gag reflex** is mediated primarily by the **glossopharyngeal nerve (CN IX)**, which detects sensation from the posterior tongue and pharynx. *Trigeminal nerve* - The **trigeminal nerve (CN V)** primarily mediates sensation from the face, teeth, and anterior two-thirds of the tongue, and motor control of the **muscles of mastication**. - It does not have a primary role in the sensation or reflex of the posterior pharyngeal wall. *Facial nerve* - The **facial nerve (CN VII)** is responsible for the **muscles of facial expression**, taste from the anterior two-thirds of the tongue, and parasympathetic innervation to several glands. - While it contributes to some aspects of swallowing, it is not the main sensory nerve for the gag reflex from the posterior pharynx. *Vagus* - The **vagus nerve (CN X)** provides the efferent limb of the gag reflex, causing pharyngeal muscle contraction. - However, the sensory input from the posterior pharynx (the afferent limb being tested by the probe) is primarily carried by the **glossopharyngeal nerve**. *Hypoglossal nerve* - The **hypoglossal nerve (CN XII)** provides motor innervation to the intrinsic and extrinsic muscles of the tongue. - While it is relevant in skull base trauma, it does not mediate sensation from the pharynx or the gag reflex being tested in the image.

Q: Which nerve is responsible for gag reflex

9th Cranial Nerve. ***9th Cranial Nerve*** - The **glossopharyngeal nerve (CN IX)** is primarily responsible for the **afferent (sensory)** limb of the gag reflex, detecting touch in the posterior pharynx. - It transmits sensory information to the **brainstem**, initiating the efferent response via the vagus nerve. - CN IX is considered the nerve "responsible for" the gag reflex as it **detects and initiates** the protective response. *10th Cranial Nerve* - The **vagus nerve (CN X)** provides the **efferent (motor)** limb of the gag reflex, causing pharyngeal muscle contraction. - While essential for the motor response, CN IX is the primary sensory trigger that initiates the reflex. - Both nerves work together, but CN IX is the **detection nerve** that starts the reflex arc. *11th Cranial Nerve* - The **spinal accessory nerve (CN XI)** primarily innervates the **sternocleidomastoid** and **trapezius muscles**, controlling head and shoulder movements. - It has no direct role in the **gag reflex**. *6th Cranial Nerve* - The **abducens nerve (CN VI)** is responsible for the **lateral rectus muscle** of the eye, controlling **abduction of the eyeball**. - It does not participate in the complex **sensory or motor pathways** of the gag reflex. *7th Cranial Nerve* - The **facial nerve (CN VII)** controls **facial expressions**, taste from the anterior two-thirds of the tongue, and some glandular secretions. - While it has some role in taste and salivation, it is not the primary nerve for the **gag reflex**.

Q: A 57-year-old man comes to the physician for a follow-up examination. During the last 6 months, he has had recurring pneumonia after undergoing a surgical operation. He reports that, when food has gone down his windpipe, he has not automatically coughed. Examination shows normal voluntary coughing, but an impaired cough reflex. The nerve responsible for this patient's symptoms is most likely damaged at which of the following anatomical sites?

Piriform recess. ***Piriform recess*** - Damage to the sensory fibers of the **internal laryngeal nerve (a branch of the superior laryngeal nerve, which comes from the vagus nerve)** in the piriform recess impairs the afferent limb of the cough reflex, specifically from the larynx above the vocal folds. - This results in the inability to automatically cough when food enters the windpipe (aspiration), explaining the recurrent pneumonia. *Foramen magnum* - Damage at the foramen magnum would typically affect structures like the **medulla oblongata** or proximal cervical spinal cord, leading to more widespread neurological deficits such as respiratory failure, severe motor and sensory deficits, or cranial nerve palsies. - Such extensive involvement is not indicated by isolated impairment of the cough reflex with normal voluntary coughing. *Aortic arch* - The **left recurrent laryngeal nerve** loops around the aortic arch, but damage here would primarily cause **hoarseness** due to vocal cord paralysis, which is not described. - While the recurrent laryngeal nerves innervate the intrinsic muscles of the larynx and provide some sensation below the vocal folds, impairment here is less likely to cause the specific symptom of absent cough reflex upon aspiration without hoarseness. *Parotid gland* - The parotid gland houses the **facial nerve (CN VII)**, which innervates muscles of facial expression, and the **auriculotemporal nerve** (a branch of CN V3) provides sensation. - Damage here would cause **facial paralysis** or sensory deficits, neither of which are consistent with an impaired cough reflex. *Infratemporal fossa* - The infratemporal fossa contains structures like the **mandibular nerve (CN V3)**, **otic ganglion**, and the **chorda tympani** (a branch of CN VII). - Damage here would typically affect mastication, sensation to the lower face, or taste, none of which explain the patient's specific symptoms related to coughing and aspiration.

A 32-year-old man presents to the emergency department with a severe headache. He says that the pain has been getting progressively worse over the last 24 hours and is located primarily in his left forehead and eye. The headaches have woken him up from sleep and it is not relieved by over-the-counter medications. He has been recovering from a sinus infection that started 1 week ago. His past medical history is significant for type 1 diabetes and he has a 10 pack-year history of smoking. Imaging shows thrombosis of a sinus above the sella turcica. Which of the following findings would most likely also be seen in this patient?

Q10

A 57-year-old man comes to the physician for a follow-up examination. During the last 6 months, he has had recurring pneumonia after undergoing a surgical operation. He reports that, when food has gone down his windpipe, he has not automatically coughed. Examination shows normal voluntary coughing, but an impaired cough reflex. The nerve responsible for this patient's symptoms is most likely damaged at which of the following anatomical sites?

Head & Neck US Medical PG Practice Questions and MCQs

Question 1: Impaired gag reflex is seen due to a lesion in which cranial nerves?

A. CN V&VI
B. CN X & XI
C. CN IX & X (Correct Answer)
D. CN VII & VIII
E. CN XI & XII

Explanation: ***Correct: CN IX & X*** The **gag reflex (pharyngeal reflex)** is a protective reflex involving two cranial nerves: - **Afferent limb**: **CN IX (Glossopharyngeal nerve)** provides sensory innervation to the posterior third of the tongue, oropharynx, and pharyngeal walls - **Efferent limb**: **CN X (Vagus nerve)** provides motor innervation to the pharyngeal muscles (via the pharyngeal plexus) that contract during the reflex **Clinical correlation**: Testing the gag reflex helps assess brainstem function and the integrity of CN IX and X. Impairment suggests lesions affecting these nerves or their nuclei in the medulla. *Incorrect: CN V & VI* - CN V (Trigeminal) provides facial sensation and motor to muscles of mastication, not involved in gag reflex - CN VI (Abducens) controls lateral rectus muscle for eye abduction *Incorrect: CN X & XI* - While CN X is involved, CN XI (Accessory nerve) innervates sternocleidomastoid and trapezius muscles, not pharyngeal muscles *Incorrect: CN VII & VIII* - CN VII (Facial) controls facial expression and taste from anterior 2/3 of tongue - CN VIII (Vestibulocochlear) is involved in hearing and balance, not the gag reflex *Incorrect: CN XI & XII* - CN XI (Accessory) innervates SCM and trapezius - CN XII (Hypoglossal) provides motor to intrinsic and extrinsic tongue muscles, not pharyngeal muscles involved in gag reflex

Question 2: Which tongue papillae do not have taste buds?

A. Fungiform
B. Filiform (Correct Answer)
C. Circumvallate
D. Foliate
E. Conical

Explanation: ***Filiform*** - **Filiform papillae** are the most abundant type of papillae on the tongue and are responsible for the **mechanical action of gripping food**, due to their cone-shaped, abrasive structure of keratinized epithelium. - Unlike other papillae, they **lack taste buds** and thus do not play a role in taste sensation. *Fungiform* - **Fungiform papillae** are mushroom-shaped and are scattered among the filiform papillae, primarily on the tip and sides of the tongue. - These papillae **contain taste buds** on their superior surface and are involved in sensing taste stimuli. *Circumvallate* - **Circumvallate papillae** are large, dome-shaped structures arranged in a V-shape at the back of the tongue. - They are surrounded by a trench into which salivary glands empty, and their walls contain a **large number of taste buds**. *Foliate* - **Foliate papillae** are leaf-like folds located on the lateral margins of the posterior tongue. - They are **well-developed in young children** and contain taste buds, though they tend to degenerate with age. *Conical* - **Conical** is not a recognized classification of tongue papillae. While filiform papillae have a conical (cone-shaped) structure, "conical papillae" is not an anatomical term used to describe a distinct type of papilla.

Question 3: Match the following nerves to their respective areas of supply to the auricle

A. A - Auriculotemporal, B - Greater auricular, C - Vagus, D - Lesser occipital (Correct Answer)
B. A - Greater auricular, B - Auriculotemporal, C - Lesser occipital, D - Vagus
C. A - Auriculotemporal, B - Lesser occipital, C - Greater auricular, D - Vagus
D. A - Auriculotemporal, B - Lesser occipital, C - Vagus, D - Greater auricular
E. A - Vagus, B - Greater auricular, C - Auriculotemporal, D - Lesser occipital

Explanation: ***A - Auriculotemporal, B - Greater auricular, C - Vagus, D - Lesser occipital*** - **A points to the anterior-superior part of the auricle**, which is supplied by the **auriculotemporal nerve**, a branch of the trigeminal nerve (CN V3). - **B points to the posterolateral surface of the auricle and the lobule**, primarily supplied by the **greater auricular nerve**, a branch of the cervical plexus (C2-C3). - **C (the concha)** is innervated by the **vagus nerve** (CN X). - **D, the superior posterior part of the auricle**, is supplied by the **lesser occipital nerve** (C2-C3). *A - Auriculotemporal, B - Lesser occipital, C - Vagus, D - Greater auricular* - This option incorrectly swaps the **lesser occipital** and **greater auricular** nerve distributions. - The **greater auricular nerve** supplies the prominent posterolateral auricle (area B), not area D. *A - Vagus, B - Greater auricular, C - Auriculotemporal, D - Lesser occipital* - This option incorrectly assigns the **vagus nerve** to area A (anterosuperior auricle), which is innervated by the **auriculotemporal nerve**. - The **auriculotemporal nerve** is incorrectly placed at C; the vagus nerve primarily innervates the concha (area C). *A - Greater auricular, B - Auriculotemporal, C - Lesser occipital, D - Vagus* - This option reverses the **greater auricular** and **auriculotemporal** distributions and misplaces the vagus and lesser occipital nerves. - The **auriculotemporal nerve** supplies the anterosuperior region (A), not the posterolateral region (B). *A - Auriculotemporal, B - Lesser occipital, C - Greater auricular, D - Vagus* - This option incorrectly places the **lesser occipital nerve** at B and misidentifies the concha's innervation. - The **greater auricular nerve** supplies area B (posterolateral auricle and lobule), not the concha (C).

Question 4: The nerve passing through the arrow-marked region in the provided image has been lesioned. Which of the following is the most likely clinical presentation?

A. Loss of sensation in the jaw area
B. Loss of sensation on the scalp and nose
C. Loss of sensation in the maxillary area of the face (Correct Answer)
D. Loss of sensation in the mucosa of nasopharynx
E. Loss of motor function to muscles of facial expression

Explanation: ***Loss of sensation in the maxillary area of the face*** - The arrow points to the **foramen rotundum**, which transmits the **maxillary nerve (V2)**, a branch of the trigeminal nerve. - Lesion of the maxillary nerve (V2) leads to sensory loss in the **maxillary region of the face**, including the cheek, upper lip, upper teeth, and palate. *Loss of sensation in the jaw area* - Sensation in the jaw area, including the lower teeth and chin, is primarily supplied by the **mandibular nerve (V3)**, which exits through the foramen ovale. - A lesion at the foramen rotundum would not directly affect V3. *Loss of sensation on the scalp and nose* - Sensation to the scalp (anterior part) and nose is primarily supplied by the **ophthalmic nerve (V1)**, which exits the skull through the superior orbital fissure. - The foramen rotundum is not involved in the passage of the ophthalmic nerve. *Loss of sensation in the mucosa of nasopharynx* - While parts of the nasopharynx mucosa receive innervation from V2, this is a very specific and limited area, and the primary and most prominent sensory loss from a V2 lesion would be in the **maxillary facial region**. - Other nerves like the glossopharyngeal nerve also contribute to nasopharyngeal sensation. *Loss of motor function to muscles of facial expression* - Motor function to muscles of facial expression is supplied by the **facial nerve (CN VII)**, not the maxillary nerve (V2). - The maxillary nerve is a purely **sensory** branch of the trigeminal nerve and has no motor function. - The facial nerve exits the skull through the stylomastoid foramen, not the foramen rotundum.

Question 5: An absent gag reflex can result from injury to which of the following nerves?

A. Cranial Nerve VII (Facial) and Cranial Nerve V (Trigeminal)
B. Cranial Nerve V (Trigeminal) and Cranial Nerve IX (Glossopharyngeal)
C. Cranial Nerve IX (Glossopharyngeal) and Cranial Nerve X (Vagus) (Correct Answer)
D. Cranial Nerve X (Vagus) and Cranial Nerve VII (Facial)
E. Cranial Nerve XII (Hypoglossal) and Cranial Nerve X (Vagus)

Explanation: ***Cranial Nerve IX (Glossopharyngeal) and Cranial Nerve X (Vagus)*** - The **gag reflex** is a protective reflex that involves both sensory and motor components. - The **glossopharyngeal nerve (CN IX)** is responsible for the **afferent (sensory)** limb, detecting stimulation of the posterior pharynx. The **vagus nerve (CN X)** is responsible for the **efferent (motor)** limb, causing contraction of pharyngeal muscles. *Cranial Nerve VII (Facial) and Cranial Nerve V (Trigeminal)* - The **facial nerve (CN VII)** primarily controls muscles of **facial expression** and taste from the anterior two-thirds of the tongue. - The **trigeminal nerve (CN V)** mediates sensation to the face, mastication, and corneal reflex, but not the gag reflex. *Cranial Nerve V (Trigeminal) and Cranial Nerve IX (Glossopharyngeal)* - While **CN IX** is indeed involved in the **sensory component of the gag reflex**, the **trigeminal nerve (CN V)** is not directly involved in either the sensory or motor pathway of the gag reflex. - The trigeminal nerve's primary roles are facial sensation and mastication. *Cranial Nerve X (Vagus) and Cranial Nerve VII (Facial)* - The **vagus nerve (CN X)** is crucial for the **motor component** of the gag reflex. - However, the **facial nerve (CN VII)** is not involved in the gag reflex; its functions relate to facial movement and taste. *Cranial Nerve XII (Hypoglossal) and Cranial Nerve X (Vagus)* - While the **vagus nerve (CN X)** does provide the **motor component** of the gag reflex, the **hypoglossal nerve (CN XII)** is not involved in this reflex. - The **hypoglossal nerve (CN XII)** controls intrinsic and extrinsic muscles of the tongue, important for tongue movement and speech, but not for the pharyngeal muscle contraction required for the gag reflex.

Question 6: Which of the following statements is true regarding the structure shown in the image?

A. Hypoglossal nerve
B. Lingual nerve (Correct Answer)
C. Nerve to mylohyoid
D. Inferior alveolar nerve
E. Glossopharyngeal nerve

Explanation: ***Lingual nerve*** - The image appears to depict a **surgical field in the floor of the mouth**, likely during an excision of a lesion, where the **lingual nerve** is a key structure that needs to be identified and preserved due to its superficial position. - The lingual nerve provides **general sensation** and **taste (chorda tympani fibers)** to the anterior two-thirds of the tongue, and its injury would result in loss of these functions. *Hypoglossal nerve* - The **hypoglossal nerve** (CN XII) innervates the **intrinsic and extrinsic muscles of the tongue** (except the palatoglossus) and is deep to the submandibular duct. - While important in floor of mouth surgery, it is typically located more inferiorly and medially, deeper than the very superficial structure shown, which appears to be the lingual nerve. *Nerve to mylohyoid* - The **nerve to mylohyoid** is a branch of the inferior alveolar nerve and innervates the **mylohyoid muscle** and the **anterior belly of the digastric muscle**. - This nerve is located more inferiorly, lying on the surface of the mylohyoid muscle, and is less likely to be the prominent superficial structure highlighted in this context near the tongue root or oral mucosa. *Inferior alveolar nerve* - The **inferior alveolar nerve** is a branch of the mandibular nerve (V3) and primarily provides **sensation to the mandibular teeth** and **gingiva**; it enters the mandibular foramen. - This nerve is located deep within the mandible and jaw, not superficially within the oral cavity or floor of the mouth as depicted, making it an unlikely choice for the superficial structure shown. *Glossopharyngeal nerve* - The **glossopharyngeal nerve** (CN IX) provides **general sensation and taste** to the **posterior one-third of the tongue** and innervates the stylopharyngeus muscle. - This nerve courses deep in the pharyngeal region and does not run superficially in the anterior floor of the mouth as shown in the image, making it an incorrect choice for this superficial anterior structure.

Question 7: A patient was admitted with skull base trauma. The doctor was testing the marked structure in the pharyngeal region. Which of the following nerves was being tested?

A. Trigeminal nerve
B. Facial nerve
C. Glossopharyngeal nerve (Correct Answer)
D. Vagus
E. Hypoglossal nerve

Explanation: ***Glossopharyngeal nerve*** - The image shows a probe stimulating the posterior part of the **pharynx**, which elicits the **gag reflex**. - The afferent limb of the **gag reflex** is mediated primarily by the **glossopharyngeal nerve (CN IX)**, which detects sensation from the posterior tongue and pharynx. *Trigeminal nerve* - The **trigeminal nerve (CN V)** primarily mediates sensation from the face, teeth, and anterior two-thirds of the tongue, and motor control of the **muscles of mastication**. - It does not have a primary role in the sensation or reflex of the posterior pharyngeal wall. *Facial nerve* - The **facial nerve (CN VII)** is responsible for the **muscles of facial expression**, taste from the anterior two-thirds of the tongue, and parasympathetic innervation to several glands. - While it contributes to some aspects of swallowing, it is not the main sensory nerve for the gag reflex from the posterior pharynx. *Vagus* - The **vagus nerve (CN X)** provides the efferent limb of the gag reflex, causing pharyngeal muscle contraction. - However, the sensory input from the posterior pharynx (the afferent limb being tested by the probe) is primarily carried by the **glossopharyngeal nerve**. *Hypoglossal nerve* - The **hypoglossal nerve (CN XII)** provides motor innervation to the intrinsic and extrinsic muscles of the tongue. - While it is relevant in skull base trauma, it does not mediate sensation from the pharynx or the gag reflex being tested in the image.

Question 8: Which nerve is responsible for gag reflex

A. 11th cranial nerve
B. 6th Cranial Nerve
C. 7th Cranial Nerve
D. 9th Cranial Nerve (Correct Answer)
E. 10th Cranial Nerve

Explanation: ***9th Cranial Nerve*** - The **glossopharyngeal nerve (CN IX)** is primarily responsible for the **afferent (sensory)** limb of the gag reflex, detecting touch in the posterior pharynx. - It transmits sensory information to the **brainstem**, initiating the efferent response via the vagus nerve. - CN IX is considered the nerve "responsible for" the gag reflex as it **detects and initiates** the protective response. *10th Cranial Nerve* - The **vagus nerve (CN X)** provides the **efferent (motor)** limb of the gag reflex, causing pharyngeal muscle contraction. - While essential for the motor response, CN IX is the primary sensory trigger that initiates the reflex. - Both nerves work together, but CN IX is the **detection nerve** that starts the reflex arc. *11th Cranial Nerve* - The **spinal accessory nerve (CN XI)** primarily innervates the **sternocleidomastoid** and **trapezius muscles**, controlling head and shoulder movements. - It has no direct role in the **gag reflex**. *6th Cranial Nerve* - The **abducens nerve (CN VI)** is responsible for the **lateral rectus muscle** of the eye, controlling **abduction of the eyeball**. - It does not participate in the complex **sensory or motor pathways** of the gag reflex. *7th Cranial Nerve* - The **facial nerve (CN VII)** controls **facial expressions**, taste from the anterior two-thirds of the tongue, and some glandular secretions. - While it has some role in taste and salivation, it is not the primary nerve for the **gag reflex**.

Question 9: A 32-year-old man presents to the emergency department with a severe headache. He says that the pain has been getting progressively worse over the last 24 hours and is located primarily in his left forehead and eye. The headaches have woken him up from sleep and it is not relieved by over-the-counter medications. He has been recovering from a sinus infection that started 1 week ago. His past medical history is significant for type 1 diabetes and he has a 10 pack-year history of smoking. Imaging shows thrombosis of a sinus above the sella turcica. Which of the following findings would most likely also be seen in this patient?

A. Anosmia
B. Mandibular pain
C. Vertigo
D. Ophthalmoplegia (Correct Answer)
E. Vision loss

Explanation: ***Ophthalmoplegia*** - **Cavernous sinus thrombosis** (thrombosis of a sinus above the sella turcica) most commonly causes palsy of cranial nerves III, IV, and VI, which pass through the cavernous sinus, leading to **ophthalmoplegia** - The patient's severe headache, particularly in the eye and forehead, progressive worsening, and history of recent sinus infection are all classic features of cavernous sinus thrombosis - The cavernous sinus contains CN III (oculomotor), CN IV (trochlear), CN VI (abducens), and branches of CN V (V1 and V2), making ophthalmoplegia the most characteristic finding *Anosmia* - While a sinus infection can lead to temporary **anosmia** (loss of smell), it is not a direct consequence of cavernous sinus thrombosis - The **olfactory nerve (CN I)** is located in the roof of the nasal cavity and passes through the cribriform plate, not through the cavernous sinus - Anosmia would be related to the preceding sinus infection itself, not the cavernous sinus thrombosis *Mandibular pain* - **Mandibular pain** would typically be associated with issues affecting the mandibular division of the trigeminal nerve **(CN V3)**, which does not pass through the cavernous sinus - Although CN V1 (ophthalmic) and CN V2 (maxillary) do pass through the cavernous sinus and could cause facial pain, the predominant pain pattern in cavernous sinus thrombosis is orbital and frontal, not mandibular - V3 exits the skull via foramen ovale and bypasses the cavernous sinus entirely *Vertigo* - **Vertigo** is a sensation of spinning or dizziness typically associated with vestibular dysfunction (inner ear or CN VIII/brainstem pathology) - It is not a common or direct symptom of **cavernous sinus thrombosis**, which primarily affects structures passing through or adjacent to the cavernous sinus - CN VIII (vestibulocochlear nerve) does not pass through the cavernous sinus *Vision loss* - While severe complications such as **optic nerve compression** from orbital swelling or **retinal venous congestion** can occur, direct **vision loss** is not the most common or earliest finding in cavernous sinus thrombosis - The **optic nerve (CN II)** does not pass through the cavernous sinus itself, though it runs nearby - Ophthalmoplegia (extraocular movement dysfunction) is far more characteristic than visual acuity loss as an initial presentation

Question 10: A 57-year-old man comes to the physician for a follow-up examination. During the last 6 months, he has had recurring pneumonia after undergoing a surgical operation. He reports that, when food has gone down his windpipe, he has not automatically coughed. Examination shows normal voluntary coughing, but an impaired cough reflex. The nerve responsible for this patient's symptoms is most likely damaged at which of the following anatomical sites?

A. Foramen magnum
B. Aortic arch
C. Piriform recess (Correct Answer)
D. Parotid gland
E. Infratemporal fossa

Explanation: ***Piriform recess*** - Damage to the sensory fibers of the **internal laryngeal nerve (a branch of the superior laryngeal nerve, which comes from the vagus nerve)** in the piriform recess impairs the afferent limb of the cough reflex, specifically from the larynx above the vocal folds. - This results in the inability to automatically cough when food enters the windpipe (aspiration), explaining the recurrent pneumonia. *Foramen magnum* - Damage at the foramen magnum would typically affect structures like the **medulla oblongata** or proximal cervical spinal cord, leading to more widespread neurological deficits such as respiratory failure, severe motor and sensory deficits, or cranial nerve palsies. - Such extensive involvement is not indicated by isolated impairment of the cough reflex with normal voluntary coughing. *Aortic arch* - The **left recurrent laryngeal nerve** loops around the aortic arch, but damage here would primarily cause **hoarseness** due to vocal cord paralysis, which is not described. - While the recurrent laryngeal nerves innervate the intrinsic muscles of the larynx and provide some sensation below the vocal folds, impairment here is less likely to cause the specific symptom of absent cough reflex upon aspiration without hoarseness. *Parotid gland* - The parotid gland houses the **facial nerve (CN VII)**, which innervates muscles of facial expression, and the **auriculotemporal nerve** (a branch of CN V3) provides sensation. - Damage here would cause **facial paralysis** or sensory deficits, neither of which are consistent with an impaired cough reflex. *Infratemporal fossa* - The infratemporal fossa contains structures like the **mandibular nerve (CN V3)**, **otic ganglion**, and the **chorda tympani** (a branch of CN VII). - Damage here would typically affect mastication, sensation to the lower face, or taste, none of which explain the patient's specific symptoms related to coughing and aspiration.

Question 11: A 28-year-old man is brought to the emergency department by ambulance after being hit in the head with a baseball bat. Physical examination shows swelling and bruising around the left temple and eye. A CT scan of the head shows a transverse fracture through the sphenoid bone and blood in the sphenoid sinus. Neurological examination is most likely to show which of the following findings?

A. Decreased hearing in the left ear
B. Deviation of uvula to the right
C. Left facial paralysis
D. Left homonymous hemianopia
E. Inward deviation of the left eye (Correct Answer)

Explanation: ***Inward deviation of the left eye*** - A fracture of the **sphenoid bone** can damage the **abducens nerve (CN VI)**, which innervates the **lateral rectus muscle**. - Paralysis of the lateral rectus muscle would cause the eye to deviate medially (inward) due to the unopposed action of the **medial rectus muscle**. *Decreased hearing in the left ear* - Hearing loss would suggest damage to the **vestibulocochlear nerve (CN VIII)** or structures of the inner ear. - While acoustic trauma or temporal bone fractures can cause hearing loss, the sphenoid fracture is less directly associated with this finding. *Deviation of uvula to the right* - Uvular deviation is typically caused by damage to the **vagus nerve (CN X)** or glossopharyngeal nerve (CN IX). - A left vagal nerve lesion would cause the uvula to deviate to the healthy, right side. *Left facial paralysis* - Facial paralysis results from damage to the **facial nerve (CN VII)**, which is commonly affected in temporal bone fractures. - While possible with severe head trauma, sphenoid bone fractures are not the primary cause of facial nerve palsy. *Left homonymous hemianopia* - **Homonymous hemianopia** indicates a lesion in the **optic tracts**, **optic radiations**, or the **occipital cortex**. - While severe head trauma can lead to intracranial hemorrhage or contusion affecting these areas, a sphenoid fracture itself is not the direct cause of this specific visual field defect.

Question 12: A 45-year-old man is brought to the emergency department after being found down in the middle of the street. Bystanders reported to the police that they had seen the man as he exited a local bar, and he was subsequently assaulted. He sustained severe facial trauma, including multiple lacerations and facial bone fractures. The man is taken to the operating room by the ENT team, who attempt to reconstruct his facial bones with multiple plates and screws. Several days later, he complains of the inability to open his mouth wide or to completely chew his food, both of which he seemed able to do prior to surgery. Which of the following is a characteristic of the injured nerve branch?

A. Parasympathetic component only
B. Sensory component only
C. Voluntary motor and sensory components (Correct Answer)
D. Voluntary motor component only
E. Sympathetic component only

Explanation: ***Voluntary motor and sensory components*** - The inability to open the mouth wide (trismus) and difficulty chewing suggests injury to the muscles of **mastication**, primarily innervated by the **mandibular branch of the trigeminal nerve (V3)**. - V3 is a mixed nerve, containing both **voluntary motor fibers** to the muscles of mastication (e.g., masseter, temporalis, pterygoids) and **sensory fibers** for general sensation of the lower face, lower lip, chin, and teeth. *Parasympathetic component only* - The **mandibular nerve (V3)** does not contain direct parasympathetic fibers; rather, preganglionic parasympathetic fibers from other cranial nerves often hitchhike along its branches to reach target glands. - **Parasympathetic fibers** primarily control glandular secretion and smooth muscle, which are not directly causative of the patient's symptoms of trismus and difficulty chewing. *Sensory component only* - While the **mandibular nerve (V3)** does provide extensive **sensory innervation** to the lower face and oral cavity, the patient's primary complaints of inability to open his mouth and chew indicate a motor deficit. - A purely sensory nerve injury would present with numbness or altered sensation, not motor dysfunction. *Voluntary motor component only* - Although the patient's symptoms are predominantly motor, the **mandibular nerve (V3)** is not purely motor; it also carries important **sensory innervation**. - A purely motor nerve injury might lead to paralysis, but the lack of mention of sensory changes doesn't exclude the sensory component of V3 from being affected or even intact. *Sympathetic component only* - The **mandibular nerve (V3)** does not contain sympathetic fibers. Sympathetic fibers typically travel with blood vessels or other nerves. - **Sympathetic innervation** primarily controls vasoconstriction, sweating, and piloerection, none of which align with the patient's reported symptoms of difficulty chewing and opening the mouth.

Question 13: A 65-year-old female with a past medical history of hypertension presents to her primary care doctor with a 3 month history of spasmodic facial pain. The pain is located in her right cheek and seems to be triggered when she smiles, chews, or brushes her teeth. The pain is sharp and excruciating, lasts for a few seconds, and occurs up to twenty times per day. She denies headaches, blurry vision, facial weakness, or changes in her memory. She feels rather debilitated and has modified much of her daily activities to avoid triggering the spasms. In the clinic, her physical exam is within normal limits. Her primary care doctor prescribes carbamazepine and asks her to follow up in a few weeks. Which cranial nerve is most likely involved in the patient's disease process?

A. CN III
B. CN V (Correct Answer)
C. CN VI
D. CN VII
E. CN IV

Explanation: ***CN V*** - The patient's presentation of **recurrent, sharp, excruciating, unilateral facial pain** triggered by movements like chewing, smiling, or brushing teeth is classic for **trigeminal neuralgia**. - **Trigeminal neuralgia** specifically affects the **trigeminal nerve (CN V)**, which has sensory branches covering the face, and is often treated with **carbamazepine**. *CN III* - The **oculomotor nerve (CN III)** is primarily involved in **eye movement** and **pupillary constriction**. - Damage to CN III typically causes **diplopia, ptosis,** and **pupil dilation**, which are not present in this patient's symptoms. *CN VI* - The **abducens nerve (CN VI)** controls the **lateral rectus muscle**, responsible for **abducting the eye** (moving it outward). - Dysfunction typically results in **diplopia** and an inability to move the eye laterally, not facial pain. *CN VII* - The **facial nerve (CN VII)** controls **facial expressions**, taste sensation from the anterior two-thirds of the tongue, and lacrimation/salivation. - While it innervates facial muscles, its involvement typically presents as **facial weakness** or **paralysis** (e.g., Bell's palsy), not sharp, spasmodic pain. *CN IV* - The **trochlear nerve (CN IV)** innervates the **superior oblique muscle**, which is involved in rotating and depressing the eye. - Lesions usually lead to **vertical diplopia**, particularly when looking down and inward, which is unrelated to the described facial pain.

Question 14: A 25-year-old man is brought to the emergency department 30 minutes after he was involved in a motorcycle collision. He was not wearing a helmet. Physical examination shows left periorbital ecchymosis. A CT scan of the head shows a fracture of the greater wing of the left sphenoid bone with compression of the left superior orbital fissure. Physical examination of this patient is most likely to show which of the following findings?

A. Complete loss of vision of the left eye
B. Decreased sense of smell
C. Absent left corneal reflex (Correct Answer)
D. Numbness of the left cheek
E. Impaired left lateral gaze

Explanation: ***Absent left corneal reflex*** - Compression of the **superior orbital fissure** damages cranial nerves passing through it, including the **ophthalmic division (V1)** of the trigeminal nerve, which mediates the **afferent limb of the corneal reflex**. - V1 damage causes loss of corneal sensation, resulting in an absent reflex. - While multiple cranial nerves traverse the superior orbital fissure (CN III, IV, V1, VI), the **corneal reflex** is a reliable and easily tested clinical sign of V1 involvement. *Complete loss of vision of the left eye* - The **optic nerve (CN II)**, responsible for vision, passes through the **optic canal**, not the superior orbital fissure. - Fractures specifically affecting the superior orbital fissure do not directly compress the optic nerve. *Decreased sense of smell* - The **olfactory nerve (CN I)**, which governs the sense of smell, passes through the **cribriform plate** of the ethmoid bone. - Injury to the greater wing of the sphenoid bone or superior orbital fissure does not affect the olfactory pathway. *Numbness of the left cheek* - Sensory innervation to the cheek is supplied by the **maxillary division (V2)** of the trigeminal nerve. - V2 exits via the **foramen rotundum**, not the superior orbital fissure, and would not be affected by this fracture. *Impaired left lateral gaze* - The **abducens nerve (CN VI)** passes through the superior orbital fissure and innervates the **lateral rectus muscle** for lateral gaze. - While CN VI damage can occur with superior orbital fissure compression and cause lateral gaze impairment, the question emphasizes the fracture of the **greater wing** with **compression** rather than complete superior orbital fissure syndrome. - In isolated compression scenarios, **sensory deficits (V1)** such as absent corneal reflex are often more readily apparent on initial examination than subtle extraocular movement limitations, making the corneal reflex a key clinical finding to assess.

Question 15: A 47-year-old woman presents to the emergency department with a fever and a headache. Her symptoms started yesterday and have rapidly progressed. Initially, she was experiencing just a fever and a headache which she was treating with acetaminophen. It rapidly progressed to blurry vision, chills, nausea, and vomiting. The patient has a past medical history of diabetes and hypertension and she is currently taking insulin, metformin, lisinopril, and oral contraceptive pills. Her temperature is 104°F (40.0°C), blood pressure is 157/93 mmHg, pulse is 120/min, respirations are 15/min, and oxygen saturation is 98% on room air. Upon further inspection, the patient also demonstrates exophthalmos in the affected eye. The patient's extraocular movements are notably decreased in the affected eye with reduced vertical and horizontal gaze. The patient also demonstrates decreased sensation near the affected eye in the distribution of V1 and V2. While the patient is in the department waiting for a CT scan, she becomes lethargic and acutely altered. Which of the following is the most likely diagnosis?

A. Acute closed angle glaucoma
B. Cavernous sinus thrombosis (Correct Answer)
C. Brain abscess
D. Periorbital cellulitis
E. Intracranial hemorrhage

Explanation: ***Cavernous sinus thrombosis*** - The rapid progression of symptoms, **exophthalmos**, decreased extraocular movements (involving cranial nerves III, IV, and VI that pass through the cavernous sinus), and V1/V2 sensory deficits (trigeminal nerve branches) are classic signs of **cavernous sinus thrombosis**. The patient's acute alteration and lethargy point to CNS involvement. - The patient's oral contraceptive use is a risk factor for **thrombosis**, and her diabetic and hypertensive status may contribute to her vulnerability to infections, which can lead to cavernous sinus thrombosis. *Acute closed angle glaucoma* - Acute closed-angle glaucoma typically presents with sudden, severe eye pain, blurred vision, and halos, often without systemic symptoms like fever or rapid progression to altered mental status. - While it causes blurry vision, it does not typically cause **exophthalmos**, multiple extraocular muscle palsies, or deficits in V1/V2 sensation. *Brain abscess* - A brain abscess can cause fever, headache, and altered mental status, but it less commonly presents with the specific combination of **exophthalmos**, multiple cranial nerve palsies affecting eye movement, and V1/V2 sensory deficits. - It would typically cause focal neurological deficits related to the specific brain region affected, rather than a constellation of orbital and systemic symptoms like this. *Periorbital cellulitis* - Periorbital cellulitis causes eyelid swelling, redness, and pain, and can be associated with fever, but it typically does not cause **exophthalmos**, decreased extraocular movements, or sensory deficits in the V1/V2 distribution as seen in this patient. - Infection is limited to tissues anterior to the orbital septum and generally resolves with antibiotics without progression to severe neurological symptoms. *Intracranial hemorrhage* - Intracranial hemorrhage can cause sudden headache, altered mental status, and focal neurological deficits, but it rarely presents with **fever**, **exophthalmos**, or the specific cranial nerve palsies described without other clear signs of a stroke (e.g., sudden weakness or speech changes). - The presence of fever and the constellation of orbital signs make hemorrhage less likely as the primary diagnosis.

Question 16: A 47-year-old man presents to you with gradual loss of voice and difficulty swallowing for the past couple of months. The difficulty of swallowing is for both solid and liquid foods. His past medical history is insignificant except for occasional mild headaches. Physical exam also reveals loss of taste sensation on the posterior third of his tongue and palate, weakness in shrugging his shoulders, an absent gag reflex, and deviation of the uvula away from the midline. MRI scanning was suggested which revealed a meningioma that was compressing some cranial nerves leaving the skull. Which of the following openings in the skull transmit the affected cranial nerves?

A. Jugular foramen (Correct Answer)
B. Foramen rotundum
C. Foramen spinosum
D. Foramen ovale
E. Foramen lacerum

Explanation: ***Jugular foramen*** - The symptoms described—loss of voice, difficulty swallowing, loss of taste on the posterior third of the tongue, absent gag reflex, and uvula deviation—point to impairment of **cranial nerves IX (glossopharyngeal), X (vagus), XI (accessory)**, which all exit the skull via the **jugular foramen**. - The **vagus nerve** (CN X) is responsible for voice and swallowing (via innervation of the pharynx and larynx), the **glossopharyngeal nerve** (CN IX) for taste from the posterior third of the tongue and the gag reflex, and the **accessory nerve** (CN XI) for shoulder shrugging (trapezius and sternocleidomastoid muscles). - Note: Loss of taste on the palate may involve CN VII (facial nerve) fibers, but the dominant clinical picture with absent gag reflex, uvula deviation, dysphagia, and dysphonia clearly indicates jugular foramen pathology. *Foramen rotundum* - The **foramen rotundum** transmits the **maxillary nerve (V2)**, a branch of the trigeminal nerve. - Damage to V2 would primarily cause sensory deficits in the midface and upper teeth, which are not described in this patient. *Foramen spinosum* - The **foramen spinosum** transmits the **middle meningeal artery** and the **meningeal branch of the mandibular nerve (V3)**. - Injury here would not explain the constellation of symptoms related to voice, swallowing, taste, or shoulder movement. *Foramen ovale* - The **foramen ovale** transmits the **mandibular nerve (V3)**, the **accessory meningeal artery**, and occasionally the superficial petrosal nerve. - Damage to V3 would result in sensory loss to the lower face and motor deficits in the muscles of mastication, which are not reported. *Foramen lacerum* - The **foramen lacerum** is filled with cartilage in vivo and does not typically transmit major neurovascular structures directly through its aperture. - The **internal carotid artery** passes superior to it, and some small nerves may traverse its vicinity, but not the specific cranial nerves indicated by the patient's symptoms.

Question 17: A 55-year-old woman presents to her family physician with a 1-week history of dizziness. She experiences spinning sensations whenever she lies down and these sensations increase when she turns her head to the right. These episodes are transient, intermittent, last for less than a minute, occur multiple times in a day, and are associated with nausea. Between the episodes, she is fine and is able to perform her routine activities. She denies fever, hearing disturbances, diplopia, tinnitus, and recent flu or viral illness. Past medical history is significant for diabetes mellitus type 2, hypertension, and hypercholesterolemia. She does not use tobacco or alcohol. Her blood pressure is 124/78 mm Hg, the heart rate is 79/min, and the respiratory rate is 13/min. During the examination, when she is asked to lie supine from a sitting position with her head rotated towards the right side at 45°, horizontal nystagmus is observed. What is the next best step in the management of this patient?

A. Dix-Hallpike maneuver
B. Epley maneuver (Correct Answer)
C. MRI of the brain with gadolinium
D. Broad-spectrum antibiotics
E. High dose steroids

Explanation: ***Epley maneuver*** - The patient's presentation with **transient, positional vertigo** triggered by head movements, associated with nausea, and demonstrating **horizontal nystagmus** on positional testing is diagnostic of **Benign Paroxysmal Positional Vertigo (BPPV)**. - Since the diagnostic positional maneuver has already been performed and BPPV is confirmed, the **next best step is canalith repositioning** using the **Epley maneuver**. - The Epley maneuver is the **gold standard treatment** for posterior canal BPPV with **70-90% success rate** after a single treatment session, and it directly addresses the underlying pathophysiology by relocating displaced otoconia. - This is recommended as **first-line treatment** by the American Academy of Otolaryngology-Head and Neck Surgery guidelines. *Dix-Hallpike maneuver* - The **Dix-Hallpike maneuver** is primarily a **diagnostic test** to confirm BPPV and identify the affected semicircular canal. - The question stem describes that a positional maneuver has already been performed with nystagmus observed, effectively confirming the diagnosis. - While repeating the diagnostic test might be considered, it is not the next management step once BPPV is confirmed. *MRI of the brain with gadolinium* - This investigation is generally reserved for patients with suspected **central causes of vertigo** or other neurological deficits. - The patient's symptoms are highly suggestive of a peripheral vestibular disorder, and the absence of **ataxia, diplopia, dysarthria**, or other focal neurological signs makes a brain MRI unnecessary at this stage. *Broad-spectrum antibiotics* - Antibiotics are used to treat **bacterial infections**, such as bacterial labyrinthitis or meningitis, which can cause vertigo. - The patient denies fever, recent infections, or other signs of infection, making antibiotic therapy inappropriate for this presentation. *High dose steroids* - Corticosteroids are sometimes used in conditions like **vestibular neuritis** or **Meniere's disease** to reduce inflammation. - The patient's symptoms are not consistent with these conditions; the positional nature of her vertigo and lack of continuous symptoms point away from an inflammatory process. - Vestibular suppressants (meclizine) may provide symptomatic relief but are **adjunctive** rather than definitive treatment for BPPV.

Question 18: A 29-year-old man presents to the emergency room with facial weakness. He first noticed that he was having trouble smiling normally while at dinner with friends the night before. He also noticed that his food had less taste than usual during the dinner. He woke up on the day of presentation with a complete inability to move the right side of his face. He recently returned from an extended camping trip in the Appalachian Mountains, but he did not find any tick bites following the camping trip. His past medical history is notable for Achilles tendonitis and carpal tunnel syndrome. He works as a computer programmer. He smokes marijuana occasionally but does not smoke cigarettes. His temperature is 98.6°F (37°C), blood pressure is 120/75 mmHg, pulse is 80/min, and respirations are 18/min. On exam, he is well-appearing in no acute distress. There is loss of facial wrinkles along the forehead, eyelids, and nasolabial folds. He is unable to completely close his right eye, raise his eyebrows, or smile with the right side of his mouth. Sensation is intact to light touch along the forehead, maxilla, and mandible bilaterally. Where is the most likely source of this patient’s lesion?

A. Superior orbital fissure
B. Petrotympanic fissure
C. Inferior orbital fissure
D. Dorsal frontal lobe
E. Stylomastoid foramen (Correct Answer)

Explanation: ***Stylomastoid foramen*** - The patient presents with classic signs of **Bell's palsy**, characterized by unilateral **facial weakness affecting both the upper and lower face**, including loss of forehead wrinkles, inability to close the eye, and loss of nasolabial folds. - The **stylomastoid foramen** is the exit point of the **facial nerve (CN VII)** from the skull, and inflammation or compression at this site is the most common cause of idiopathic facial nerve paralysis (Bell's palsy). *Superior orbital fissure* - Lesions in the **superior orbital fissure** would primarily affect cranial nerves **III, IV, V1, and VI**, leading to symptoms like ophthalmoplegia, ptosis, and sensory loss in the V1 distribution of the face, not a facial nerve palsy. - While it is a bony canal, it is not the primary exit for the facial nerve. *Petrotympanic fissure* - The **petrotympanic fissure** transmits the **chorda tympani nerve**, which carries taste sensation from the anterior two-thirds of the tongue and parasympathetic fibers to the submandibular and sublingual glands. - A lesion here would cause **loss of taste** and potentially dry mouth, but would not typically explain the extensive motor deficits of the entire ipsilateral face as seen in this patient, which indicates a more proximal or complete facial nerve involvement. *Inferior orbital fissure* - The **inferior orbital fissure** transmits the **maxillary nerve (V2)**, the zygomatic nerve, and branches of the inferior ophthalmic vein, affecting sensation to the mid-face. - Damage here would result in **sensory deficits in the V2 distribution** and potentially orbital symptoms, not motor weakness of the facial muscles. *Dorsal frontal lobe* - A lesion in the **dorsal frontal lobe**, specifically involving the **motor cortex**, would cause contralateral facial weakness. However, it would typically spare the forehead and eyelid muscles due to bilateral cortical innervation of the upper facial muscles. - The patient's presentation of **forehead and entire facial weakness** is characteristic of a **lower motor neuron lesion** of the facial nerve, not a central (upper motor neuron) lesion.

Question 19: An 87-year-old male presents to his neurologist for a follow-up visit. He is being followed for an inoperable tumor near his skull. He reports that he recently noticed that food has started to lose its taste. He also notes increasing difficulty with swallowing. He has a history of myocardial infarction, diabetes mellitus, hyperlipidemia, hypertension, and presbycusis. He takes aspirin, metoprolol, metformin, glyburide, atorvastatin, lisinopril, and hydrochlorothiazide. On examination, the patient is a frail-appearing male sitting in a wheelchair. He is oriented to person, place, and time. Gag reflex is absent on the right side. A taste evaluation is performed which demonstrates a decreased ability to detect sour and bitter substances on the right posterior tongue. The nerve responsible for this patient’s loss of taste sensation also has which of the following functions?

A. Somatic sensory innervation to the roof of the pharynx
B. Parasympathetic innervation to the trachea
C. Somatic sensory innervation to the lower lip
D. Parasympathetic innervation to the parotid gland (Correct Answer)
E. Parasympathetic innervation to the submandibular gland

Explanation: ***Parasympathetic innervation to the parotid gland*** - The patient's symptoms, including loss of taste on the **right posterior tongue**, difficulty swallowing, and an absent gag reflex, point to an issue with the **glossopharyngeal nerve (CN IX)**. - The glossopharyngeal nerve provides **parasympathetic innervation to the parotid gland** via the otic ganglion, stimulating saliva production. *Somatic sensory innervation to the roof of the pharynx* - The glossopharyngeal nerve (CN IX) does provide somatic sensory innervation to the pharynx, but specifically the **posterior 1/3 of the tongue**, tonsils, and part of the pharynx, not primarily the roof. - While related to the pharynx, this option is not the most precise or unique function associated with the primary nerve implicated here. *Parasympathetic innervation to the trachea* - **Parasympathetic innervation to the trachea** is primarily mediated by the **vagus nerve (CN X)**, which innervates the smooth muscle and glands of the trachea and bronchi. - The glossopharyngeal nerve (CN IX) does not have a direct role in tracheal innervation. *Somatic sensory innervation to the lower lip* - **Somatic sensory innervation to the lower lip** is primarily provided by the **mental nerve**, a branch of the **trigeminal nerve (CN V)**. - The glossopharyngeal nerve (CN IX) is not involved in sensory innervation of the lower lip. *Parasympathetic innervation to the submandibular gland* - **Parasympathetic innervation to the submandibular and sublingual glands** is provided by the **facial nerve (CN VII)** via the submandibular ganglion. - This function is distinct from the glossopharyngeal nerve's role in innervating the parotid gland.

Question 20: A 55-year-old woman with a 1-year history of left-sided tinnitus is diagnosed with a tumor at the left cerebellopontine angle affecting the glossopharyngeal nerve. Sialometry shows decreased production of saliva from the left parotid gland. The finding on sialometry is best explained by a lesion of the nerve that is also responsible for which of the following?

A. Protrusion of the tongue
B. Afferent limb of the cough reflex
C. Afferent limb of the gag reflex (Correct Answer)
D. Equilibrium and balance
E. Taste sensation of tip of the tongue

Explanation: ***Afferent limb of the gag reflex*** - The **glossopharyngeal nerve (CN IX)** provides **parasympathetic innervation** to the **parotid gland**, explaining the decreased saliva production on sialometry. - CN IX is also responsible for the **afferent limb of the gag reflex** and taste sensation from the posterior one-third of the tongue. *Protrusion of the tongue* - **Protrusion of the tongue** is primarily controlled by the **hypoglossal nerve (CN XII)**. - A lesion affecting the glossopharyngeal nerve would not directly impact the ability to protrude the tongue. *Afferent limb of the cough reflex* - The **afferent limb of the cough reflex** is primarily mediated by the **vagus nerve (CN X)**, which innervates the laryngeal and tracheobronchial mucosa. - While there can be some overlap, the glossopharyngeal nerve is not the primary mediator for this reflex. *Equilibrium and balance* - **Equilibrium and balance** are primarily maintained by the **vestibulocochlear nerve (CN VIII)**, which is responsible for transmitting vestibular information. - A lesion of the glossopharyngeal nerve would not primarily affect these functions, although cerebellopontine angle tumors can affect CN VIII. *Taste sensation of tip of the tongue* - **Taste sensation from the anterior two-thirds of the tongue** (including the tip) is conveyed by the **facial nerve (CN VII)** via the chorda tympani. - The glossopharyngeal nerve (CN IX) provides taste sensation to the posterior one-third of the tongue.

Question 21: A 45-year-old man is brought to the emergency department after being found down in the middle of the street. Bystanders reported to the police that they had seen the man as he exited a local bar, where he was subsequently assaulted. He sustained severe facial trauma, including multiple lacerations and facial bone fractures. The man is taken to the operating room by the ENT team, who attempted to reconstruct his facial bones with multiple plates and screws. Several days later, he complains of the inability to open his mouth wide or to completely chew his food, both of which he seemed able to do prior to the surgery. Where does the affected nerve exit the skull?

A. Foramen rotundum
B. Foramen ovale (Correct Answer)
C. Jugular foramen
D. Superior orbital fissure
E. Inferior orbital fissure

Explanation: ***Foramen ovale*** - The symptoms of inability to open the mouth wide and difficulty chewing are indicative of damage to the **motor branches of the trigeminal nerve (mandibular nerve)**, which innervates the muscles of mastication. - The **mandibular nerve (V3)** exits the skull through the **foramen ovale**. *Foramen rotundum* - The **foramen rotundum** transmits the **maxillary nerve (V2)**, which is primarily sensory to the midface. - Damage to this nerve would cause sensory deficits in the cheek, upper lip, and teeth, but not issues with mastication. *Jugular foramen* - The **jugular foramen** transmits the **glossopharyngeal (IX)**, **vagus (X)**, and **accessory (XI)** cranial nerves. - Damage here would lead to problems with swallowing, speech, gag reflex, or shoulder movement, not specifically jaw movement or chewing. *Superior orbital fissure* - The **superior orbital fissure** transmits the **oculomotor (III)**, **trochlear (IV)**, **ophthalmic (V1)**, and **abducens (VI)** cranial nerves. - Damage here would primarily affect eye movements or sensation around the eye and forehead. *Inferior orbital fissure* - The **inferior orbital fissure** transmits the **infraorbital nerve** (a branch of V2), **zygomatic nerve**, and other vessels. - Damage here would result in sensory deficits in the infraorbital region and potentially affect lacrimal gland function, but not mastication.

Question 22: A 72-year-old woman presents to the emergency department for vision loss. She was reading a magazine this afternoon when she started having trouble seeing out of her left eye. Her vision in that eye got progressively darker, eventually becoming completely black over the course of a few minutes. It then returned to normal after about 10 minutes; she reports she can see normally now. She had no pain and no other symptoms then or now. Past medical history is notable for hypertension and hyperlipidemia. A high-pitched sound is heard when the diaphragm of the stethoscope is placed on her left neck, but her physical exam is otherwise unremarkable; vision is currently 20/30 bilaterally. The etiology of her symptoms most likely localizes to which of the following anatomic locations?

A. Left atrium
B. Subclavian artery
C. Temporal artery
D. Carotid artery (Correct Answer)
E. Vertebral artery

Explanation: ***Carotid artery*** - The sudden, temporary vision loss (amaurosis fugax) in one eye, described as a "curtain coming down," is a classic symptom of an **embolus originating from the ipsilateral carotid artery**. - The **bruit** heard in the left neck further points to significant **carotid artery stenosis**, which can be a source of these emboli to the **ophthalmic artery**. *Left atrium* - An embolus from the left atrium (e.g., in atrial fibrillation) would typically cause symptoms of a **cerebral stroke** or vision loss in **both eyes** if it affects a major supplying vessel before the intracranial branches, or could affect the carotid artery system, but the neck bruit directly implicates the carotid. - While a source of emboli, the direct finding of a neck bruit makes the carotid the more immediate and specific localization. *Subclavian artery* - **Subclavian artery** stenosis can cause **subclavian steal syndrome**, leading to vertebrobasilar insufficiency and symptoms like **dizziness** or **syncope**, but generally does not cause unilateral amaurosis fugax. - Its territory primarily supplies the arm and posterior circulation, not the anterior cerebral circulation or ophthalmic artery directly as suggested by amaurosis fugax. *Temporal artery* - **Temporal arteritis** (Giant Cell Arteritis) can cause sudden vision loss, often irreversible, and is usually associated with **headaches**, **jaw claudication**, and a very high **ESR**, none of which are reported here. - While it affects the ophthalmic artery, the absence of pain and the transient nature of the vision loss (amaurosis fugax) make it less likely than an embolic event. *Vertebral artery* - The **vertebral arteries** supply the **posterior circulation** of the brain, leading to symptoms such as **diplopia**, **vertigo**, **ataxia**, or **hemiparesis**, but not isolated unilateral amaurosis fugax. - Problems in this artery typically manifest as **vertebrobasilar insufficiency**, which affects both eyes or causes other brainstem symptoms, not transient unilateral blindness.

Question 23: A 12-year-old boy is brought in by his mother with a 2-day history of fever and generalized weakness. She says that her son was involved in a school fight with some other kids 4 days ago and sustained minor injuries to the face. He was otherwise well, until this morning, when he complained of pain in his right eye. Physical examination reveals periorbital erythema and edema of the right eye, along with ophthalmoplegia and proptosis. Which of the following findings will most likely be present in this patient on the affected side as a sequela of his current condition?

A. Anesthesia along the CN V3 distribution
B. Intact sympathetic innervation to the pupil, but not parasympathetic innervation
C. Monocular diplopia
D. Absent blink reflex
E. Decreased vision with optic disc swelling (Correct Answer)

Explanation: ***Decreased vision with optic disc swelling*** - The patient's presentation with **periorbital erythema**, **edema**, **ophthalmoplegia**, and **proptosis** suggests **orbital cellulitis** or a related orbital infection, potentially progressing to **cavernous sinus thrombosis**. - This condition can lead to compression of the **optic nerve**, resulting in **decreased vision** and **optic disc swelling** due to impaired venous outflow and elevated intraorbital pressure. *Anesthesia along the CN V3 distribution* - **Anesthesia along the CN V3 (mandibular nerve) distribution** is unlikely as orbital infections and cavernous sinus thrombosis primarily affect structures superior and medial to the orbit, involving CN V1 (ophthalmic) and CN V2 (maxillary) divisions if facial sensation is implicated. - CN V3 involvement would typically arise from pathology within or inferior to the cavernous sinus, which is not the primary site of injury in this presentation. *Intact sympathetic innervation to the pupil, but not parasympathetic innervation* - This statement describes a specific pattern of autonomic dysfunction affecting the pupil, such as in **Horner's syndrome (sympathetic denervation)** or **oculomotor nerve palsy (parasympathetic denervation)**. - While the oculomotor nerve (CN III) is often affected in orbital cellulitis or cavernous sinus thrombosis, causing ophthalmoplegia, the question describes a combination of symptoms that more directly point to **optic nerve compression** rather than isolated pupillary changes. *Monocular diplopia* - **Monocular diplopia** typically results from optical abnormalities within one eye, such as **cataracts**, **astigmatism**, or **corneal irregularities**, where light is split before reaching the retina. - The patient's symptoms of ophthalmoplegia and proptosis suggest involvement of **extraocular muscles** and nerves, which would more commonly cause **binocular diplopia** (double vision that resolves when one eye is closed) due to misalignment of the eyes. *Absent blink reflex* - The **blink reflex** involves the **trigeminal nerve (afferent limb)** and the **facial nerve (efferent limb)**. While the trigeminal nerve's ophthalmic division (CN V1) might be affected by orbital pathology or cavernous sinus thrombosis, leading to decreased sensation, a complete absence of the blink reflex is a severe sign. - The more direct and common sequela of the described proptosis and ophthalmoplegia affecting visual function and optic nerve health is **decreased vision with optic disc swelling**.

Question 24: A 30-year-old man comes to the physician because of recurrent episodes of right-sided jaw pain over the past 3 months. The patient describes the pain as dull. He says it worsens throughout the day and with chewing, and that it can also be felt in his right ear. He also reports hearing a cracking sound while eating. Over the past 2 months, he has had several episodes of severe headache that improves slightly with ibuprofen intake. Vital signs are within normal limits. Physical examination shows limited jaw opening. Palpation of the face shows facial muscle spasms. Which of the following is the most likely underlying cause of this patient's symptoms?

A. Chronic inflammation of the sinuses
B. Dental abscess
C. Dysfunction of the temporomandibular joint (Correct Answer)
D. Trigeminal nerve compression
E. Infection of the mandible

Explanation: ***Dysfunction of the temporomandibular joint*** - The patient's symptoms of **right-sided jaw pain** that worsens with chewing, radiating to the ear, a **cracking sound during eating**, and **limited jaw opening** are classic indicators of **temporomandibular joint (TMJ) dysfunction**. - **Facial muscle spasms** and associated **headaches** are also common manifestations of TMJ disorders, which can be triggered by stress or bruxism. *Chronic inflammation of the sinuses* - Sinusitis typically presents with **facial pain and pressure**, usually around the eyes and forehead, and can be accompanied by **nasal discharge**, congestion, and fever. - While headaches can occur, the prominent jaw symptoms, cracking sounds, and aggravation with chewing are not characteristic of chronic sinusitis. *Dental abscess* - A dental abscess would cause **localized, severe throbbing pain** in a tooth, which might radiate but would not typically present with the described widespread jaw symptoms, cracking, or limited range of motion. - It would also likely involve **swelling, tenderness to percussion**, and possibly pus discharge. *Trigeminal nerve compression* - **Trigeminal neuralgia** presents with **sudden, severe, brief, shock-like pain** in the distribution of one or more branches of the trigeminal nerve, often triggered by light touch, chewing, or speaking. - The patient's symptoms of dull, worsening pain with activity and cracking sounds are inconsistent with the paroxysmal nature of trigeminal neuralgia. *Infection of the mandible* - An infection of the mandible (osteomyelitis) would present with **severe pain, swelling, erythema**, and potentially fever and systemic signs of infection. - The chronicity, association with chewing, and cracking sounds are not typical of mandibular osteomyelitis in its presentation.

Question 25: An otherwise healthy 45-year-old man comes to the physician because of a painful ulcer on his tongue for 3 days. Examination shows a shallow, tender 5-mm wide ulcer on the lateral aspect of the tongue, adjacent to his left first molar. There is no induration surrounding the ulcer or cervical lymphadenopathy. A lesion of the cranial nerve responsible for the transmission of pain from this ulcer would most likely result in which of the following?

A. Loss of taste from the supraglottic region
B. Lateral deviation of the tongue
C. Inability to wrinkle the forehead
D. Decreased sensation in the upper lip
E. Loss of sensation in the anterior two-thirds of the tongue (Correct Answer)

Explanation: ***Loss of sensation in the anterior two-thirds of the tongue*** - The sensation of pain from the **anterior two-thirds of the tongue** is transmitted by the **lingual nerve**, which is a branch of the mandibular division (V3) of the **trigeminal nerve**. A lesion affecting this nerve would therefore cause loss of sensation in this region. - The ulcer is located on the **lateral aspect of the tongue**, placing it within the distribution of the lingual nerve. *Loss of taste from the supraglottic region* - **Taste sensation** from the **supraglottic region** and epiglottis is primarily mediated by the **superior laryngeal nerve** (a branch of the vagus nerve, CN X), not the nerve responsible for pain sensation from the anterior tongue. - A lesion of the lingual nerve would affect taste sensation from the **anterior two-thirds of the tongue** (carried by the chorda tympani, a branch of CN VII, which joins the lingual nerve), but not the supraglottic region. *Lateral deviation of the tongue* - **Lateral deviation of the tongue** (towards the side of the lesion) occurs due to damage to the **hypoglossal nerve (CN XII)**, which innervates the intrinsic and extrinsic muscles of the tongue. - This is a motor deficit, whereas the question describes a sensory issue related to pain transmission from an ulcer on the tongue. *Inability to wrinkle the forehead* - The **inability to wrinkle the forehead** (along with other facial expressions) results from damage to the **facial nerve (CN VII)**, specifically its temporal branch. - This is a motor deficit affecting the muscles of facial expression, unrelated to pain sensation from the tongue. *Decreased sensation in the upper lip* - **Sensation in the upper lip** is supplied by the **infraorbital nerve**, a branch of the maxillary division (V2) of the **trigeminal nerve**. - A lesion affecting the nerve responsible for pain from the anterior two-thirds of the tongue (lingual nerve, V3) would not directly impact sensation in the upper lip.

Question 26: A 27-year-old man presents to a physician for evaluation of 3 months of increased vertigo. He says that occasionally he will experience several seconds of intense vertigo that makes him lose his balance. He came in for evaluation because this symptom is affecting his ability to drive to work. He has also been occasionally experiencing tinnitus. Physical exam reveals rotatory nystagmus that is delayed in onset and stops with visual fixation. The nerve that is most likely causing these symptoms exits the skull at which of the following locations?

A. Internal auditory meatus (Correct Answer)
B. Cribriform plate
C. Foramen ovale
D. Jugular foramen
E. Foramen rotundum

Explanation: ***Internal auditory meatus*** - The symptoms described, particularly **vertigo** and **tinnitus**, are indicative of an issue with the **vestibulocochlear nerve (CN VIII)**. - The **vestibulocochlear nerve** exits the skull through the **internal auditory meatus**, which is also the pathway for the **facial nerve (CN VII)**. *Cribriform plate* - The **cribriform plate** is associated with the passage of the **olfactory nerves (CN I)**, which are responsible for the sense of smell. - Damage to this area would typically cause **anosmia**, not vertigo or tinnitus. *Foramen ovale* - The **foramen ovale** is the exit point for the **mandibular nerve (V3)**, a branch of the trigeminal nerve. - Dysfunction here would lead to problems with **mastication** or altered sensation in the lower face, not vertigo. *Jugular foramen* - The **jugular foramen** transmits several cranial nerves: the **glossopharyngeal (CN IX)**, **vagus (CN X)**, and **accessory (CN XI)** nerves. - Issues in this region would manifest as difficulties with **swallowing**, **speech**, or **shoulder/neck movement**, not balance or hearing. *Foramen rotundum* - The **foramen rotundum** transmits the **maxillary nerve (V2)**, another branch of the trigeminal nerve. - Damage to this nerve would primarily affect **sensation in the middle third of the face**, not balance or hearing.

Question 27: A 28-year-old man comes to the physician because of a persistent tingling sensation in the right side of his face. The sensation began after he underwent an extraction of an impacted molar 2 weeks ago. Examination shows decreased sensation of the skin over the right side of the mandible, chin, and the anterior portion of the tongue. Taste sensation is preserved. The affected nerve exits the skull through which of the following openings?

A. Foramen rotundum
B. Hypoglossal canal
C. Foramen magnum
D. Foramen ovale (Correct Answer)
E. Stylomastoid foramen

Explanation: ***Foramen ovale*** - This patient presents with **paresthesia** in the distribution of branches of the **mandibular nerve (V3)** following molar extraction. The affected areas (mandible, chin, and anterior tongue sensation) indicate injury to the **inferior alveolar nerve** (lower teeth, chin, lower lip) and/or **lingual nerve** (general sensation to anterior 2/3 of tongue). - Both the **inferior alveolar nerve** and **lingual nerve** are branches of the **mandibular nerve (V3)**, which exits the skull through the **foramen ovale**. These nerves run in close proximity during molar extraction and are commonly injured together. - Taste sensation is preserved because the **chorda tympani** (taste fibers from CN VII) travels with the lingual nerve but does not exit through foramen ovale. *Foramen rotundum* - The **foramen rotundum** transmits the **maxillary nerve (V2)**, which innervates the midface, upper teeth, and palate. - Injury to this nerve would cause sensory deficits in the upper lip and cheek, not the mandible or chin. *Hypoglossal canal* - The **hypoglossal canal** transmits the **hypoglossal nerve (CN XII)**, which is a motor nerve to the intrinsic and extrinsic muscles of the tongue. - Damage to this nerve would result in **tongue weakness** or **atrophy**, not sensory changes to the face or tongue. *Foramen magnum* - The **foramen magnum** is the largest opening in the skull, transmitting the **spinal cord**, vertebral arteries, and accessory nerve (CN XI). - Damage here would likely involve severe neurological deficits, not isolated sensory loss to the lower face. *Stylomastoid foramen* - The **stylomastoid foramen** transmits the **facial nerve (CN VII)**, which is primarily responsible for facial expression and taste sensation to the anterior two-thirds of the tongue via the chorda tympani. - While CN VII provides taste to the tongue, it does not provide general sensory innervation to the skin of the mandible or chin, and taste is preserved in this patient.

Question 28: A 55-year-old woman comes to the physician because of a 2-week history of painful swelling on the right side of her face. The pain worsens when she eats. Examination of the face shows a right-sided, firm swelling that is tender to palpation. Oral examination shows no abnormalities. Ultrasonography shows a stone located in a duct that runs anterior to the masseter muscle and passes through the buccinator muscle. Sialoendoscopy is performed to remove the stone. At which of the following sites is the endoscope most likely to be inserted during the procedure?

A. Lateral to the lingual frenulum
B. Into the floor of the mouth
C. Lateral to the superior labial frenulum
D. Into the mandibular foramen
E. Opposite the second upper molar tooth (Correct Answer)

Explanation: ***Opposite the second upper molar tooth*** - The description of the duct running anterior to the **masseter muscle** and through the **buccinator muscle** is characteristic of the **parotid duct (Stensen's duct)**. - The parotid duct opens into the oral cavity on the buccal mucosa **opposite the second upper molar tooth**, which is the most likely entry point for sialoendoscopy to remove a stone from this duct. *Lateral to the lingual frenulum* - This location is where the **submandibular duct (Wharton's duct)** opens into the oral cavity. - While stones can occur in the submandibular duct, the patient's symptoms and the duct's anatomical description do not match this location. *Into the floor of the mouth* - The floor of the mouth is the general area where the submandibular and sublingual ducts open. - However, the specific anatomical description of the duct in relation to the masseter and buccinator muscles points away from the submandibular/sublingual glands. *Lateral to the superior labial frenulum* - This area is associated with the openings of minor salivary glands in the upper lip. - These glands are typically too small to be the source of such a prominent swelling or a large stone requiring sialoendoscopy. *Into the mandibular foramen* - The **mandibular foramen** is an opening on the medial surface of the mandibular ramus. - It is an anatomical landmark for the **inferior alveolar nerve and vessels** and has no direct involvement in salivary gland duct openings.

Question 29: A 37-year-old machinist presents to his primary care physician with eye problems. The patient states that he has had a mass in his eye that has persisted for the past month. The patient has a past medical history of blepharitis treated with eye cleansing and squamous cell carcinoma of the skin treated with Mohs surgery. His temperature is 99.5°F (37.5°C), blood pressure is 157/102 mmHg, pulse is 90/min, respirations are 17/min, and oxygen saturation is 98% on room air. Physical exam is notable for a firm and rubbery nodule palpable inside the patient's left eyelid. Physical exam does not elicit any pain. Which of the following is the most likely diagnosis?

A. Meibomian gland carcinoma
B. Chalazion (Correct Answer)
C. Hordeolum
D. Ingrown eyelash follicle
E. Foreign body

Explanation: ***Chalazion*** - This patient's presentation of a **firm, rubbery, painless nodule** inside the eyelid, persistent for a month, is characteristic of a **chalazion**. It often develops after a hordeolum or **blepharitis** due to obstruction of a Meibomian gland. - Chalazia are typically **non-tender** as they represent a chronic, sterile inflammation rather than an acute infection. *Meibomian gland carcinoma* - While a Meibomian gland carcinoma can present as a nodule, it often shows suggestive signs like **loss of eyelashes (madarosis)**, ulceration, or recurrent chalazion in an elderly patient. This patient's presentation does not describe these features. - Carcinomas tend to be more **invasive** and may present with less defined borders or rapid growth, which are not mentioned here. *Hordeolum* - A **hordeolum (stye)** is an acute, painful, localized infection of an eyelash follicle (**external hordeolum**) or Meibomian gland (**internal hordeolum**). - It would typically cause **pain, redness, and tenderness** which are absent in this patient's description. *Ingrown eyelash follicle* - An ingrown eyelash (trichiasis) primarily causes **irritation, foreign body sensation**, and possibly corneal abrasion from the misdirected lash rubbing against the eye. - It does not typically present as a firm, rubbery, painless nodule *inside* the eyelid, but rather as an eyelash growing inwards. *Foreign body* - A foreign body in the eye would typically cause acute onset of **pain, irritation, tearing**, and potentially redness. - The persistent, painless, firm nodule described is less consistent with a foreign body, which would usually be more symptomatic or eventually expelled.

Question 30: A 69-year-old man comes to the physician with a 2-year history of progressive hearing loss. His hearing is worse in crowded rooms, and he has noticed that he has more difficulty understanding women than men. He has no history of serious illness and does not take any medications. A Rinne test shows air conduction is greater than bone conduction bilaterally. This condition is most likely associated with damage closest to which of the following structures?

A. Tympanic membrane
B. Round window
C. Base of the stapes
D. External acoustic meatus
E. Basal turn of the cochlea (Correct Answer)

Explanation: ***Basal turn of the cochlea*** - The patient's presentation of progressive hearing loss, difficulty hearing in crowded rooms (**presbycusis**), and trouble understanding women's voices (higher frequencies) is characteristic of **sensorineural hearing loss**. - The **basal turn of the cochlea** is responsible for detecting high-frequency sounds, making it the most likely site of damage in presbycusis. *Tympanic membrane* - Damage to the **tympanic membrane** would typically result in a **conductive hearing loss**, characterized by bone conduction being greater than air conduction (abnormal Rinne test). - The patient's Rinne test shows air conduction greater than bone conduction, indicating a sensorineural or normal hearing pattern. *Round window* - The **round window** plays a role in relieving pressure in the cochlea, allowing fluid movement and sound transmission. - While damage here can affect hearing, it's not the primary site of progressive, age-related high-frequency sensorineural loss. *Base of the stapes* - Issues at the **base of the stapes**, particularly **otosclerosis**, cause **conductive hearing loss** due to the ossification of the oval window, hindering sound transmission. - This would present with an abnormal Rinne test (BC > AC), which is not observed in this patient. *External acoustic meatus* - Obstruction or damage to the **external acoustic meatus** (e.g., earwax impaction, otitis externa) would cause a **conductive hearing loss**. - The Rinne test would show bone conduction greater than air conduction, which is inconsistent with the patient's findings.

Question 31: A 28-year-old woman comes to the physician because of a 1-year history of intermittent buzzing in both her ears. She says she sometimes has episodes of mild dizziness which resolve spontaneously. She has a 15-year history of type 1 diabetes mellitus and episodes of low back pain. She does not smoke or drink alcohol. Current medications include insulin and aspirin. She works as a trombonist for a symphony orchestra. Her vital signs are within normal limits. On otoscopic examination, the tympanic membrane appears normal. Bone conduction is greater than air conduction in both ears. Weber test shows no lateralization. Which of the following is the most likely diagnosis?

A. Presbycusis
B. Diabetic otopathy
C. Drug-induced ototoxicity
D. Otosclerosis (Correct Answer)
E. Endolymphatic hydrops

Explanation: ***Otosclerosis*** - The combination of **conductive hearing loss** (**bone conduction > air conduction**), **intermittent buzzing (tinnitus)**, and mild dizziness in a young adult is characteristic of otosclerosis. The normal tympanic membrane further supports this diagnosis as it indicates no external or middle ear infection/perforation. - **Weber test shows no lateralization** because the conductive hearing loss is **symmetric and bilateral**, meaning both ears are equally affected. *Presbycusis* - This is an age-related **sensorineural hearing loss** that typically affects older individuals, usually over 50-60 years old, not a 28-year-old. - Presbycusis usually presents with **air conduction > bone conduction** (sensorineural pattern) and affects high frequencies first, not conductive hearing loss. *Diabetic otopathy* - While patients with long-standing diabetes can develop hearing loss, it is typically a **sensorineural hearing loss** due to microvascular damage, not conductive hearing loss. - The symptoms in diabetic otopathy usually involve high-frequency hearing loss and are not typically associated with bone conduction exceeding air conduction. *Drug-induced ototoxicity* - **Aspirin** can cause tinnitus and sensorineural hearing loss, but the presented case demonstrates **conductive hearing loss** (bone conduction > air conduction). - Aspirin ototoxicity typically causes reversible sensorineural hearing loss and tinnitus, not the conductive pattern seen here. *Endolymphatic hydrops* - Also known as **Meniere's disease**, this condition causes episodic **vertigo, tinnitus, and sensorineural hearing loss**. - The hearing loss is typically **sensorineural** and often fluctuating, while this patient presents with signs of **conductive hearing loss**.

Question 32: A 26-year-old woman comes to the physician because of a progressive swelling in her mouth that she first noticed 5 years ago. Initially, the swelling was asymptomatic but has now caused some difficulty while chewing food for the past month. She has no pain. She has not undergone any dental procedures in the past 5 years. She has bronchial asthma. Her only medication is an albuterol inhaler. She appears healthy. Her temperature is 37°C (98.6°F), pulse is 70/min, and blood pressure is 110/70 mm Hg. Examination shows a 1.5-cm smooth, unilobular, bony hard, nontender mass in the midline of the hard palate. There is no cervical or submandibular lymphadenopathy. The remainder of the examination shows no abnormalities. Which of the following is the most likely diagnosis?

A. Palatal abscess
B. Palatal pleomorphic adenoma
C. Necrotizing sialometaplasia
D. Nasopalatine duct cyst
E. Torus palatinus (Correct Answer)

Explanation: ***Torus palatinus*** - This is a **benign bony protuberance** found on the hard palate, characterized by a **slow-growing, asymptomatic, hard, nontender mass** in the midline of the hard palate, consistent with the patient's presentation. - Its progressive growth over 5 years causing difficulty with chewing due to its size, without pain or other symptoms, is typical of this condition. *Palatal abscess* - A palatal abscess would present with **significant pain**, redness, swelling, and often fever, indicative of an **acute infection**, which is absent here. - Dental procedures or trauma often precede abscess formation, and the patient reports no recent procedures. *Palatal pleomorphic adenoma* - This is a benign tumor of salivary glands, often presenting as a **slow-growing, painless mass**, but it is typically **softer or rubbery** in consistency, not "bony hard," and often occurs eccentrically rather than exactly in the midline. - While it can grow large, its consistency and typical location make it less likely than torus palatinus in this specific midline, bony hard presentation. *Necrotizing sialometaplasia* - This is an **inflammatory, usually ulcerative lesion of salivary glands** that can be painful and often heals spontaneously. - It would present as a rapidly developing, painful ulcer or swelling, not a slow-growing, bony hard, nontender mass. *Nasopalatine duct cyst* - This is a **non-odontogenic cyst** typically located in the **midline of the anterior hard palate**, behind the incisors, but it is characteristically a **fluid-filled lesion** and would usually be **compressible or fluctuant**, not bony hard. - While it can be asymptomatic and grow slowly, its consistency differentiates it from a bony growth.

Question 33: A 52-year-old diabetic man presents with fever, headache, and excruciating pain in his right eye for the past 2 days. He says that he has been taking sitagliptin and metformin regularly. He endorses recently having a sore throat. On examination, vesicles are present in groups with an erythematous base on the upper eyelid, forehead, and nose on the right half of his face. The patient is prescribed an antiviral agent and sent home. Which of the following nerves is most likely involved?

A. Ophthalmic nerve (Correct Answer)
B. Supraorbital nerve
C. Nasociliary nerve
D. Supratrochlear nerve
E. Lacrimal nerve

Explanation: ***Ophthalmic nerve*** - The ophthalmic nerve (V1) is the most likely involved due to the characteristic **vesicular rash** in a **dermatomal distribution** on the upper eyelid, forehead, and nose, along with **severe eye pain**. This presentation is consistent with **herpes zoster ophthalmicus**. - The ophthalmic nerve provides sensory innervation to these areas, and its involvement indicates a **reactivation of varicella-zoster virus** in the trigeminal ganglion affecting the V1 division. *Supraorbital nerve* - The supraorbital nerve is a branch of the **ophthalmic nerve (V1)**, primarily innervating the skin of the **forehead and scalp**. - While lesions described are on the forehead, involvement of the **upper eyelid and nose** indicates a broader distribution than just the supraorbital nerve. *Nasociliary nerve* - The nasociliary nerve is a branch of the **ophthalmic nerve (V1)** that innervates the **cornea, conjunctiva, iris, ciliary body, and parts of the nose**. - While eye pain and nasal involvement could point to nasociliary involvement, the comprehensive presentation across the **forehead, eyelid, and nose** suggests involvement of the entire V1 division. *Supratrochlear nerve* - The supratrochlear nerve is another branch of the **ophthalmic nerve (V1)**, providing sensation to the **medial part of the upper eyelid and forehead**. - Its limited distribution means it cannot account for the **entire spectrum of affected areas**, including the lateral forehead and nose. *Lacrimal nerve* - The lacrimal nerve, also a branch of the **ophthalmic nerve (V1)**, innervates the **lacrimal gland**, conjunctiva, and skin of the **lateral upper eyelid**. - Its involvement would not explain the vesicular rash observed on the **forehead and nose**.

Question 34: A 52-year-old woman presents to her primary care physician with a 1-week history of facial drooping. Specifically, she has noticed that the left side of her face does not move when she tries to smile. Furthermore, she has been having difficulty closing her left eye. Her past medical history is significant for hypertension but she does not have any known prior neurological deficits. Imaging reveals a cranial mass that is compressing an adjacent nerve. Which tumor location would most likely be associated with this patient's symptoms?

A. Jugular foramen
B. Optic canal
C. Superior orbital fissure
D. Internal auditory meatus (Correct Answer)
E. Foramen ovale

Explanation: ***Internal auditory meatus*** - This location is traversed by the **facial nerve (CN VII)** and the **vestibulocochlear nerve (CN VIII)**. Compression here would directly affect the facial nerve, causing the described **facial drooping** and **difficulty closing the eye**. - The symptoms of **facial weakness** and inability to close the eye are classic signs of a **facial nerve palsy**, which can be caused by a mass compressing the nerve in this confined space. *Jugular foramen* - This foramen transmits **cranial nerves IX (glossopharyngeal), X (vagus), and XI (accessory)**. - Compression in this area would primarily lead to symptoms such as **dysphagia**, **hoarseness**, or **shoulder/neck weakness**, not facial drooping or difficulty closing the eye. *Optic canal* - The optic canal transmits the **optic nerve (CN II)** and the **ophthalmic artery**. - Compression here would cause **visual disturbances**, such as **vision loss** or **visual field defects**, and would not affect facial muscle movement. *Superior orbital fissure* - This fissure transmits **cranial nerves III (oculomotor), IV (trochlear), VI (abducens)**, and the **ophthalmic division of CN V (trigeminal)**. - Compression in this region would result in symptoms like **diplopia**, **ptosis**, or **sensory deficits in the forehead**, not facial drooping. *Foramen ovale* - The foramen ovale transmits the **mandibular division of the trigeminal nerve (V3)**. - Compression here would cause sensory loss or motor weakness in the **muscles of mastication**, leading to difficulty chewing, but not facial drooping.

Question 35: A 23-year-old man comes to the physician because of a whistling sound during respiration for the past 3 weeks. He reports that the whistling is becoming louder, and is especially loud when he exercises. He says the noise is frustrating for him. Six months ago, the patient underwent outpatient treatment for an uncomplicated nasal fracture after being hit in the nose by a high-velocity stray baseball. Since the accident, the patient has been taking aspirin for pain. He has a history of asymptomatic nasal polyps. His temperature is 37°C (98.6°F), pulse is 70/min, respirations are 12/min, and blood pressure is 110/70 mm Hg. Physical examination shows no abnormalities. Which of the following, if performed immediately after the initial nasal fracture, would have prevented the whistling during respiration?

A. Nasal polyp removal
B. Nasal septal hematoma drainage (Correct Answer)
C. Septoplasty
D. Antibiotic therapy
E. Rhinoplasty

Explanation: ***Nasal septal hematoma drainage*** - The whistling sound is indicative of a **nasal septal perforation**, likely caused by pressure necrosis from an undrained septal hematoma after the nasal fracture. - Prompt drainage of a **nasal septal hematoma** would relieve pressure on the septum and prevent necrosis, thus averting a perforation and the subsequent whistling. *Nasal polyp removal* - While the patient has asymptomatic nasal polyps, they are generally not the cause of a whistling sound during respiration unless they are obstructing the airway completely, which typically manifests as difficulty breathing rather than isolated whistling. - Uncomplicated nasal polyps are **unlikely to cause septal perforation** or the specific symptom of a whistling noise when other potential causes are present. *Septoplasty* - Septoplasty is a surgical procedure to correct a **deviated nasal septum**, improving airflow and resolving issues like difficulty breathing or recurrent sinusitis. - It is performed for a deviated septum but would not have prevented a **septal hematoma-induced perforation** if the hematoma itself was not addressed. *Antibiotic therapy* - Antibiotic therapy would primarily be indicated for **bacterial infections**, such as those that might arise from an infected hematoma or a complicated fracture. - While an infected hematoma could worsen the outcome, antibiotics alone would not prevent the **mechanical damage and pressure necrosis** that leads to perforation from an undrained hematoma. *Rhinoplasty* - Rhinoplasty is a cosmetic surgical procedure to **reshape the nose**, primarily focusing on its external appearance. - It is not indicated for preventing or treating complications like **septal hematomas** or perforations after an acute nasal fracture.

Question 36: A 61-year-old man sustains an intracranial injury to a nerve that also passes through the parotid gland. Which of the following is a possible consequence of this injury?

A. Changes in hearing (Correct Answer)
B. Horner's syndrome
C. Paralysis of lateral rectus muscle
D. Loss of taste from posterior 1/3 of tongue
E. Loss of general sensation in anterior 2/3 of tongue

Explanation: ***Changes in hearing*** - The **facial nerve (CN VII)** is the only cranial nerve that has both an **intracranial course** and passes **through the parotid gland**. - The facial nerve gives off the **nerve to stapedius muscle** within the facial canal (before it exits the stylomastoid foramen). - Damage to this nerve can lead to **hyperacusis** (increased sensitivity to sound), as the stapedius normally dampens excessive sound vibrations. - **Note**: Facial nerve injury would also cause facial paralysis (the most prominent feature), loss of taste from anterior 2/3 of tongue via chorda tympani, and decreased lacrimation/salivation, but these are not among the answer choices. *Horner's syndrome* - This syndrome results from damage to the **sympathetic pathway** (hypothalamus → spinal cord → superior cervical ganglion → eye). - Characterized by **ptosis**, **miosis**, and **anhidrosis**. - Not related to facial nerve injury. *Paralysis of lateral rectus muscle* - The **lateral rectus muscle** is innervated by the **abducens nerve (CN VI)**. - CN VI does not pass through the parotid gland. *Loss of taste from posterior 1/3 of tongue* - Taste from the **posterior 1/3 of the tongue** is carried by the **glossopharyngeal nerve (CN IX)**. - CN IX does not pass through the parotid gland. - **Note**: The facial nerve actually carries taste from the **anterior 2/3** of the tongue via the chorda tympani branch. *Loss of general sensation in anterior 2/3 of tongue* - **General sensation** (touch, pain, temperature) from the **anterior 2/3 of the tongue** is carried by the **lingual nerve** (branch of CN V3). - The lingual nerve does not pass through the parotid gland.

Question 37: A 14-year-old boy presents to the emergency department with an intractable nosebleed. Pinching of the nose has failed to stop the bleed. The patient is otherwise healthy and has no history of trauma or hereditary bleeding disorders. His temperature is 98.9°F (37.2°C), blood pressure is 120/64 mmHg, pulse is 85/min, respirations are 12/min, and oxygen saturation is 98% on room air. Physical exam is notable for multiple clots in the nares which, when dislodged, are followed by bleeding. Which of the following locations is the most likely etiology of this patient's symptoms?

A. Ethmoidal artery
B. Kiesselbach plexus (Correct Answer)
C. Sphenopalatine artery
D. Carotid artery
E. Greater palatine artery

Explanation: ***Kiesselbach plexus*** - The **Kiesselbach plexus** (Little's area) is a common site for **anterior epistaxis**, especially in children and adolescents, because it is an aggregation of multiple converging arteries in the anterior septum. - The failure of simple pressure and the patient's age make this region the most likely source for this intractable nosebleed due to its friability and common exposure to dryness or minor trauma. *Ethmoidal artery* - The ethmoidal arteries supply the **superior and posterior nasal cavities** and contribute to posterior epistaxis, which is typically more severe and less responsive to conservative measures. - While an ethmoidal artery bleed could be intractable, it is generally less common than a Kiesselbach plexus bleed in a 14-year-old without trauma. *Sphenopalatine artery* - The **sphenopalatine artery** is a major contributor to **posterior epistaxis**, characterized by profuse bleeding that often drains into the pharynx, making it difficult to control with anterior packing. - Though it can cause severe, intractable nosebleeds, it's less frequently the initial source in a young patient compared to the anterior septum, and the presentation doesn't strongly suggest posterior bleeding (e.g., blood flowing down the throat). *Greater palatine artery* - The **greater palatine artery** is a branch of the maxillary artery that supplies the hard palate and can contribute to posterior nasal bleeding, though it is less commonly implicated in epistaxis than the sphenopalatine or ethmoidal arteries. - Bleeding from this vessel would typically present with posterior drainage and would be uncommon in a 14-year-old without trauma or other risk factors. *Carotid artery* - The carotid artery system is the primary blood supply to the nasal cavity, but a direct carotid artery bleed into the nose is **extremely rare** and usually due to severe trauma or erosion by a tumor or aneurysm. - Such a bleed would be catastrophic and present with signs of critical hemorrhage, vastly different from this patient's relatively stable vital signs.

Question 38: A professional musician visits his physician after a morning concert. He complains of painless swelling in his right cheek when he plays his tuba. Physical examination of the patient reveals slight facial asymmetry due to minor swelling on the right side of the face. The skin over the swelling is smooth without any secondary changes. Palpation reveals a soft and non-tender swelling. The oral opening is normal without any trismus. Further examination reveals swelling of the right buccal mucosa extending from the first to the third molar. Bedside ultrasound shows small areas of high echogenicity consistent with pneumoparotid. Which nerve is associated with motor function to prevent air from entering the affected duct in this patient?

A. CN VII – Zygomatic branch
B. V3 – Mandibular nerve
C. CN VII – Buccal branch (Correct Answer)
D. CN VII – Marginal mandibular branch
E. V2 – Maxillary nerve

Explanation: ***CN VII – Buccal branch*** - The **buccal branch** of the facial nerve (CN VII) innervates the **buccinator muscle**, which is crucial in preventing air from entering Stensen's duct during playing a wind instrument. - **Pneumoparotid** results from air reflux into the parotid duct, typically prevented by the buccinator muscle's action in compressing the duct opening. *CN VII – Zygomatic branch* - The **zygomatic branch** of the facial nerve innervates muscles around the **eyes**, primarily controlling eyelid closure and facial expressions in that region. - It does not directly affect the muscles responsible for preventing air entry into the parotid duct. *V3 – Mandibular nerve* - The **mandibular nerve (V3)** is a branch of the trigeminal nerve and provides **sensory innervation** to the lower face, as well as **motor innervation** to the muscles of mastication. - Its primary role is in chewing and sensation, not in controlling the buccinator muscle or preventing parotid duct air entry. *CN VII – Marginal mandibular branch* - The **marginal mandibular branch** of the facial nerve innervates the muscles of the **lower lip and chin**, controlling expressions like frowning and pouting. - It does not have a direct role in the function of the buccinator muscle or preventing air from entering the parotid duct. *V2 – Maxillary nerve* - The **maxillary nerve (V2)** is a branch of the trigeminal nerve that provides **sensory innervation** to the midface, upper teeth, and palate. - It has no motor function related to the muscles of facial expression or the prevention of pneumoparotid.

Question 39: A 65-year-old man presents with facial weakness. He says he noticed that his face appeared twisted when he looked in the bathroom mirror this morning. He is otherwise well and does not have any other complaints. He denies any facial pain or paresthesia. No significant past medical history. The patient is afebrile and vital signs are within normal limits. Neurological examination reveals difficulty shutting the right eye tight and inability to bring up the right corner of his mouth when asked to smile. Remainder of the exam, including the left side of the face, is unremarkable. Which of the following is the most likely diagnosis in this patient?

A. Idiopathic facial paralysis (Correct Answer)
B. Right hemisphere stroke
C. Left middle cerebral artery stroke
D. Facial nerve schwannoma
E. Acoustic neuroma

Explanation: ***Idiopathic facial paralysis*** - The sudden onset of **unilateral facial weakness** affecting both the upper and lower face (inability to shut eye and inability to smile on the same side) without other neurological symptoms is characteristic of **Bell's palsy**. - It is a diagnosis of exclusion, and the absence of other symptoms and normal vital signs support this benign, self-limiting condition. *Right hemisphere stroke* - A stroke typically causes **upper motor neuron facial weakness**, primarily affecting the **lower half of the contralateral face**, sparing the forehead. - Would likely present with other neurological deficits such as **hemiparesis** or sensory changes, which are absent here. *Left middle cerebral artery stroke* - Similar to a right hemisphere stroke, a left MCA stroke would typically cause **contralateral facial weakness**, predominantly in the **lower face**. - Would also likely present with additional symptoms such as **aphasia** (if the dominant hemisphere is affected) or right-sided motor/sensory deficits, which are not described. *Facial nerve schwannoma* - This condition tends to cause a **slowly progressive facial weakness**, not the acute onset described. - Often associated with other symptoms such as **persistent facial pain** or paresthesia, which this patient denies. *Acoustic neuroma* - Primarily causes **hearing loss** and **tinnitus**, and later, **vestibular symptoms** like dizziness or imbalance. - While it can eventually compress the facial nerve causing weakness, the onset would be gradual and accompanied by **auditory symptoms**, which are absent here.

Question 40: A 50-year-old man is brought in by ambulance to the emergency department with difficulty breathing and speaking. His wife reports that he might have swallowed a fishbone. While taking his history the patient develops a paroxysmal cough. Visualization of his oropharynx and larynx shows a fishbone lodged in the right piriform recess. After successfully removing the fishbone the patient feels comfortable, but he is not able to cough like before. Damage to which of the following nerves is responsible for the impaired cough reflex in this patient?

A. Inferior laryngeal nerve
B. Internal laryngeal nerve (Correct Answer)
C. External laryngeal nerve
D. Superior laryngeal nerve
E. Recurrent laryngeal nerve

Explanation: ***Internal laryngeal nerve*** - The internal laryngeal nerve is the **sensory nerve** of the larynx above the vocal cords, including the piriform recess. Damage to this nerve, often due to trauma from a foreign body like a fishbone, impairs the **afferent limb of the cough reflex**. - A fishbone lodged in the **piriform recess** directly implicates the sensory function of the internal laryngeal nerve, explaining the subsequent loss of the cough reflex even after removal of the foreign body. *Inferior laryngeal nerve* - This nerve is primarily **motor** to almost all intrinsic laryngeal muscles and provides **sensory innervation** below the vocal folds. Damage would primarily affect phonation (hoarseness) or breathing due to vocal cord paralysis. - It would not directly affect the sensory input initiating a cough reflex from the piriform recess, which is above the vocal folds. *External laryngeal nerve* - The external laryngeal nerve is a **motor nerve** supplying the **cricothyroid muscle**, which is responsible for tensing the vocal cords and altering voice pitch. - Damage to this nerve would lead to **hoarseness** and difficulty with high-pitched sounds, not an impaired cough reflex from the piriform recess. *Superior laryngeal nerve* - The superior laryngeal nerve divides into the internal and external laryngeal nerves. While it contains sensory fibers that lead to the internal laryngeal nerve, stating damage to the entire superior laryngeal nerve is less specific than identifying the internal laryngeal nerve as the direct cause of the sensory deficit. - Damage to the superior laryngeal nerve would encompass both sensory and motor deficits (internal and external branches), but the specific symptom of impaired cough reflex primarily points to the internal laryngeal branch. *Recurrent laryngeal nerve* - This nerve is another name for the **inferior laryngeal nerve** and is primarily **motor** to the intrinsic laryngeal muscles (except cricothyroid) and provides sensory innervation below the vocal cords. - Damage to this nerve primarily results in **vocal cord paralysis** and voice changes (hoarseness), not the sensory loss affecting the cough reflex from the piriform recess.

Question 41: A 27-year-old man comes to the physician because of a 1-day history of right-sided facial weakness and sound intolerance. Three days ago, he hit the right side of his head in a motor vehicle collision. He neither lost consciousness nor sought medical attention. Physical examination shows drooping of the mouth on the right side. Sensation over the face is not impaired. Impedance audiometry shows an absence of the acoustic reflex in the right ear. Which of the following muscles is most likely paralyzed in this patient?

A. Anterior belly of the digastric
B. Stylopharyngeus
C. Cricothyroid
D. Tensor tympani
E. Stylohyoid (Correct Answer)

Explanation: ***Stylohyoid*** - The patient presents with **facial nerve (CN VII) injury** following head trauma, evidenced by **facial weakness** and **hyperacusis** (sound intolerance). - The **absent acoustic reflex** indicates paralysis of the **stapedius muscle** (the primary muscle responsible for the acoustic reflex and sound dampening). - Among the options provided, **stylohyoid** is the only muscle innervated by the **facial nerve (CN VII)**, making it the correct answer in this context. - The stylohyoid is innervated by the **nerve to stylohyoid**, a branch of CN VII. *Anterior belly of the digastric* - The **anterior belly of the digastric** is innervated by the **mylohyoid nerve**, a branch of the **trigeminal nerve (CN V3)**. - This would not be affected in facial nerve injury. *Stylopharyngeus* - The **stylopharyngeus muscle** is innervated by the **glossopharyngeal nerve (CN IX)**. - Damage would cause **dysphagia** and **loss of taste** on the posterior third of the tongue, not facial weakness or hyperacusis. *Cricothyroid* - The **cricothyroid muscle** is innervated by the **external branch of the superior laryngeal nerve** (from **vagus nerve, CN X**). - Its paralysis causes **voice changes** and difficulty with high-pitched phonation, not facial nerve symptoms. *Tensor tympani* - The **tensor tympani muscle** is innervated by the **nerve to tensor tympani**, a branch of the **trigeminal nerve (V3)**. - Although it dampens sound, it would not be affected in facial nerve injury; the **stapedius muscle** (CN VII) is responsible for the acoustic reflex and hyperacusis when paralyzed.

Question 42: A 50-year-old man undergoes parathyroidectomy for treatment-resistant hyperparathyroidism. The procedure is complicated by brisk bleeding from the superior thyroid artery near the external branch of the superior laryngeal nerve. To stop the bleeding, the artery is ligated at its origin. Which of the following is most likely the origin of the artery that was injured in this patient?

A. Thyrocervical trunk
B. Ascending pharyngeal artery
C. Internal carotid artery
D. Subclavian artery
E. External carotid artery (Correct Answer)

Explanation: ***External carotid artery*** - The **superior thyroid artery** is the first branch to arise from the **external carotid artery** in the neck. - Ligation of this artery at its origin is a common surgical maneuver to control bleeding during thyroid or parathyroid surgery. *Thyrocervical trunk* - The **thyrocervical trunk** is a branch of the **subclavian artery** and gives rise to the inferior thyroid artery, not the superior thyroid artery. - Injury to the superior thyroid artery would not necessitate ligation of a vessel originating from the thyrocervical trunk. *Ascending pharyngeal artery* - The **ascending pharyngeal artery** is a small artery that branches from the **external carotid artery** but supplies the pharynx, not the thyroid gland. - It is not typically implicated in bleeding during parathyroidectomy or in relation to the superior laryngeal nerve. *Internal carotid artery* - The **internal carotid artery** primarily supplies the brain and does not have branches in the neck that supply the thyroid or parathyroid glands. - It arises from the common carotid artery but does not give off the superior thyroid artery. *Subclavian artery* - The **subclavian artery** gives rise to the **thyrocervical trunk**, which then supplies the inferior thyroid artery, but not directly the superior thyroid artery. - The superior thyroid artery originates higher up from the external carotid artery.

Question 43: A 54-year-old woman comes to the emergency department because of drooping on the left side of her face since that morning. She also reports difficulty closing her eyes and chewing. During the neurologic examination, the physician asks the patient to open her jaw against resistance. Which of the following muscles is most likely activated in this movement?

A. Hyoglossus
B. Masseter
C. Orbicularis oris
D. Buccinator
E. Lateral pterygoid (Correct Answer)

Explanation: ***Lateral pterygoid*** - The **lateral pterygoid muscle** is the primary muscle responsible for **opening the jaw (depressing the mandible)** and protruding it. - When opening the jaw against resistance, this muscle would be actively engaged and contracting to overcome the opposing force. *Hyoglossus* - The **hyoglossus muscle** is a muscle of the tongue, primarily involved in **depressing and retracting the tongue**. - It does not play a role in the movement of the jaw itself. *Masseter* - The **masseter muscle** is one of the primary muscles of **mastication**, responsible for **closing the jaw (elevating the mandible)** and clenching the teeth. - It would be active during jaw closure against resistance, not during jaw opening. *Orbicularis oris* - The **orbicularis oris muscle** surrounds the mouth and is responsible for **pursing the lips**, closing the mouth, and other facial expressions related to the mouth. - It is not involved in the movement of the jaw itself. *Buccinator* - The **buccinator muscle** is a facial muscle that forms the wall of the cheek and is involved in **compressing the cheek** (e.g., during blowing or sucking) and keeping food pocketed during chewing. - It does not directly participate in the opening or closing of the jaw joint.

Question 44: A 38-year-old woman undergoes hemithyroidectomy for treatment of localized, well-differentiated papillary thyroid carcinoma. The lesion is removed with clear margins. However, during the surgery, a structure lying directly adjacent to the superior thyroid artery at the upper pole of the thyroid lobe is damaged. This patient is most likely to experience which of the following symptoms?

A. Shortness of breath
B. Weakness of shoulder shrug
C. Voice pitch limitation (Correct Answer)
D. Difficulty swallowing
E. Ineffective cough

Explanation: ***Voice pitch limitation*** - Damage to the structure directly adjacent to the **superior thyroid artery** at the upper pole of the thyroid likely involves the **external branch of the superior laryngeal nerve (EBSLN)**. - This nerve innervates the **cricothyroid muscle**, which is responsible for **tensing the vocal cords** and controlling **voice pitch**. - Injury results in inability to change pitch, voice fatigue during prolonged speaking, and reduced vocal range. *Shortness of breath* - While damage to other nerves like the **recurrent laryngeal nerve** could cause vocal cord paralysis and potentially lead to airway compromise, this is less directly associated with the superior thyroid artery. - Shortness of breath is not the specific consequence of EBSLN injury near the superior thyroid artery. *Weakness of shoulder shrug* - Weakness of shoulder shrug is associated with damage to the **spinal accessory nerve (cranial nerve XI)**, which innervates the **trapezius muscle**. - This nerve is anatomically distinct from structures near the superior thyroid artery at the upper pole of the thyroid. *Difficulty swallowing* - Difficulty swallowing (dysphagia) can result from damage to the **vagus nerve (cranial nerve X)** or its pharyngeal branches, but it is not the direct consequence of injury near the superior thyroid artery. - Damage to the EBSLN primarily affects voice pitch and quality, not swallowing. *Ineffective cough* - An ineffective cough results from paralysis of the vocal cords (preventing glottic closure) or weakness of respiratory muscles, typically from **recurrent laryngeal nerve** damage or phrenic nerve injury. - EBSLN damage primarily affects voice pitch and does not significantly impair cough effectiveness.

Practice by Chapter

Skull and cranial cavity

Practice Questions

Face and scalp

Practice Questions

Orbital structures

Practice Questions

Ear anatomy and vestibular system

Practice Questions

Nasal cavity and paranasal sinuses

Practice Questions

Oral cavity and pharynx

Practice Questions

Larynx and vocal apparatus

Practice Questions

Triangles of the neck

Practice Questions

Deep structures of the neck

Practice Questions

Cranial nerves and their pathways

Practice Questions

Cervical sympathetic chain

Practice Questions

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free

Head & Neck — MCQs

Head & Neck — MCQs

On this page

Practice by Chapter

Want unlimited practice?