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?
Q32
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?
Q33
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?
Q34
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?
Q35
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?
Q36
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?
Q37
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?
Q38
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?
Q39
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?
Q40
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?
Head & Neck US Medical PG Practice Questions and MCQs
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. Maxillary 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.
