Head — MCQs

Head Indian Medical PG Practice Questions and MCQs

Question 691: Which of the following is not a voluntary extraocular muscle?

A. Superior rectus
B. Superior oblique
C. Superior tarsal muscle (Correct Answer)
D. Levator palpebrae superioris

Explanation: ### Explanation The key to answering this question lies in distinguishing between **striated (skeletal)** muscles, which are under voluntary control, and **smooth** muscles, which are under autonomic (involuntary) control. **Why Option C is Correct:** The **Superior tarsal muscle (Müller’s muscle)** is a thin layer of **smooth muscle** located deep to the levator palpebrae superioris. It is innervated by **sympathetic fibers** (postganglionic fibers from the superior cervical ganglion) [2]. Because it is smooth muscle and controlled by the autonomic nervous system, it is **involuntary**. Its primary function is to maintain the elevation of the upper eyelid after it has been raised by the levator muscle. **Why the Other Options are Incorrect:** * **A & B (Superior rectus and Superior oblique):** These are part of the six classic extraocular muscles that move the eyeball [1]. Like all muscles of the orbit derived from periocular mesenchyme, they are **striated skeletal muscles** under voluntary control (innervated by CN III and CN IV, respectively) [1]. * **D (Levator palpebrae superioris):** This is the primary elevator of the upper eyelid. It is a **striated muscle** innervated by the oculomotor nerve (CN III) and is under voluntary control. **High-Yield Clinical Pearls for NEET-PG:** * **Horner’s Syndrome:** Loss of sympathetic supply to the superior tarsal muscle leads to **partial ptosis** (drooping of the eyelid). This is distinct from the **complete ptosis** seen in CN III palsy (loss of Levator palpebrae superioris). * **Innervation Rule:** All extraocular muscles are supplied by CN III, except the **Superior Oblique (CN IV)** and **Lateral Rectus (CN VI)**—remember the formula **SO4LR6** [1]. * **Smooth Muscles of the Eye:** There are three main involuntary muscles in the ocular region: the **ciliary muscle**, the **sphincter pupillae**, and the **superior/inferior tarsal muscles**.

Question 692: All of the following structures are contained within the cavernous sinus EXCEPT:

A. Occulomotor nerve
B. Abducens nerve
C. Mandibular nerve (Correct Answer)
D. Maxillary nerve

Explanation: The cavernous sinus is a large venous plexus located on either side of the body of the sphenoid bone. Understanding its contents is a high-yield topic for NEET-PG, as it requires distinguishing between structures embedded in the **lateral wall** versus those passing **through the center**. ### Why Mandibular Nerve (V3) is the Correct Answer: The Trigeminal nerve (CN V) divides into three branches. While the **Ophthalmic (V1)** and **Maxillary (V2)** nerves pass through the lateral wall of the cavernous sinus, the **Mandibular nerve (V3)** does not. Instead, it descends directly from the trigeminal ganglion to exit the skull through the **foramen ovale**, bypassing the cavernous sinus entirely. ### Analysis of Incorrect Options: * **Abducens Nerve (CN VI):** This is the only cranial nerve that travels through the **center** of the sinus, situated inferolateral to the internal carotid artery. It is often the first nerve affected in cavernous sinus pathology (e.g., cavernous sinus thrombosis). * **Oculomotor Nerve (CN III):** Located in the **lateral wall** of the sinus, it is the most superiorly placed nerve in the wall. * **Maxillary Nerve (V2):** Located in the lower part of the **lateral wall** before it exits via the foramen rotundum. ### High-Yield Clinical Pearls: * **Contents of the Lateral Wall (Superior to Inferior):** CN III, CN IV, V1, and V2. * **Contents passing through the Center:** Internal Carotid Artery (ICA) and CN VI. * **Cavernous Sinus Thrombosis:** Classically presents with ophthalmoplegia (paralysis of eye muscles) and loss of sensation in the V1/V2 distribution. The **Abducens nerve** is typically involved first because it lies freely within the sinus rather than being protected within the dural wall.

Question 693: Which bone is considered the mobile bone of the skull?

A. Maxilla
B. Mandible (Correct Answer)
C. Ethmoid
D. Sphenoid

Explanation: **Explanation:** The skull is composed of 22 bones, which are categorized into the cranium (8 bones) and the facial skeleton (14 bones). All these bones are joined together by fibrous joints called **sutures**, which are immovable (synarthroses). The **Mandible** (lower jaw) is the only exception to this rule. **Why Mandible is the Correct Answer:** The mandible is the only bone of the skull that possesses a synovial joint—the **Temporomandibular Joint (TMJ)**. This articulation between the condylar process of the mandible and the mandibular fossa of the temporal bone allows for various movements such as depression, elevation, protrusion, retraction, and lateral rotation, which are essential for mastication and speech. **Why Other Options are Incorrect:** * **Maxilla:** Known as the "upper jaw," it is firmly fused to the surrounding facial bones (like the zygomatic and nasal bones) via sutures, making it stationary. * **Ethmoid:** A deep-seated cranial bone forming the roof of the nasal cavity and part of the orbits; it is fixed and immobile. * **Sphenoid:** Often called the "keystone" of the cranial base because it articulates with almost every other bone of the skull; it is entirely immobile. **High-Yield Clinical Pearls for NEET-PG:** * **Ossification:** The mandible is the second bone in the body to start ossifying (after the clavicle). * **Development:** It develops from the **1st Pharyngeal Arch** (Meckel’s cartilage). * **Nerve Supply:** The muscles moving this mobile bone are supplied by the **Mandibular nerve (V3)**, the only division of the Trigeminal nerve with motor fibers. * **Fracture Site:** The most common site of fracture in the mandible is the **neck of the condyle**, followed by the angle and symphysis.

Question 694: A 10-year-old girl admitted with tonsillitis undergoes tonsillectomy. One week post-operatively, physical examination reveals an absence of the gag reflex on the left when the posterior tongue is depressed. The sensory component of which cranial nerve was most likely injured during the procedure?

A. Facial nerve
B. Glossopharyngeal nerve (Correct Answer)
C. Mandibular nerve
D. Maxillary nerve

Explanation: The **Glossopharyngeal nerve (CN IX)** provides the sensory innervation to the posterior one-third of the tongue and the oropharyngeal mucosa, including the tonsillar fossa. It also serves as the **afferent (sensory) limb of the gag reflex**. During a tonsillectomy, the nerve is vulnerable to injury as it lies deep to the tonsillar bed, specifically in the lateral wall of the pharynx. Damage to this nerve results in the loss of the gag reflex on the ipsilateral side when the posterior tongue or oropharynx is stimulated. **Analysis of Incorrect Options:** * **Facial nerve (CN VII):** Provides taste to the anterior two-thirds of the tongue (via chorda tympani) and motor supply to muscles of facial expression. It is not involved in the gag reflex. * **Mandibular nerve (V3):** Provides general sensation to the anterior two-thirds of the tongue (via the lingual nerve). It does not supply the posterior tongue or the oropharynx. * **Maxillary nerve (V2):** Provides sensory innervation to the mid-face, upper teeth, and palate, but not the oropharyngeal area involved in the gag reflex. **NEET-PG High-Yield Pearls:** * **Gag Reflex:** Afferent limb = CN IX (Glossopharyngeal); Efferent limb = CN X (Vagus). * **Tonsillar Bed Anatomy:** The glossopharyngeal nerve and the facial artery (specifically the tonsillar branch) are the most important structures related to surgical complications in this region. * **Taste/Sensation Summary:** Posterior 1/3 of tongue = CN IX for both taste and general sensation. Anterior 2/3 = CN VII (taste) and V3 (general sensation).

Question 695: The lymphatics from the median part of the forehead drain to which of the following lymph nodes?

A. Submandibular nodes (Correct Answer)
B. Submental nodes
C. Preauricular parotid nodes
D. Upper deep cervical nodes

Explanation: ### Explanation The lymphatic drainage of the face generally follows the course of the facial arteries and veins. The drainage of the forehead is divided into two distinct zones: 1. **Median Part:** Lymphatics from the central part of the forehead, the frontal sinus, the medial part of the eyelids, and the external nose drain into the **submandibular lymph nodes**. This occurs because the vessels follow the facial vein downward toward the submandibular region. 2. **Lateral Part:** Lymphatics from the lateral part of the forehead and the lateral halves of the eyelids drain into the **preauricular (parotid) lymph nodes**. #### Analysis of Options: * **A. Submandibular nodes (Correct):** As stated above, the median part of the forehead, along with the upper lip and lateral parts of the lower lip, drains here. * **B. Submental nodes:** These nodes primarily receive drainage from the **central part of the lower lip**, the floor of the mouth, and the tip of the tongue. They do not receive drainage from the forehead. * **C. Preauricular parotid nodes:** These nodes drain the **lateral part** of the forehead, the temporal region, and the lateral parts of the eyelids. * **D. Upper deep cervical nodes:** While all head and neck lymph eventually drains into the deep cervical chain, they are not the *primary* (first-level) nodes for the forehead. #### High-Yield NEET-PG Pearls: * **The "Face Rule":** Most of the face drains into the submandibular nodes, EXCEPT the tip of the tongue, the central lower lip, and the chin (Submental), and the lateral forehead/temple (Preauricular). * **Scalp Drainage:** The anterior part of the scalp drains to the parotid nodes, while the posterior part drains to the mastoid and occipital nodes. * **Clinical Correlation:** In cases of infections or malignancies of the medial forehead, the submandibular region must be palpated for lymphadenopathy.

Question 696: Which artery does not supply the tonsil?

A. Lingual artery
B. Facial artery
C. Maxillary artery
D. Temporal artery (Correct Answer)

Explanation: The palatine tonsil is a highly vascular structure located in the tonsillar fossa of the oropharynx. Its blood supply is derived from several branches of the **External Carotid Artery (ECA)**. ### **Explanation of the Correct Answer** **D. Temporal Artery:** The superficial temporal artery is a terminal branch of the ECA that supplies the scalp, temporalis muscle, and parotid gland. It is located superior and lateral to the oral cavity and does not contribute to the blood supply of the tonsil. ### **Analysis of Incorrect Options** The tonsil is supplied by five main arterial branches: * **A. Lingual Artery:** Supplies the tonsil via its **dorsal lingual branches**. * **B. Facial Artery:** Provides the **tonsillar artery** (the main source of supply) and the **ascending palatine artery**. * **C. Maxillary Artery:** Supplies the tonsil via the **descending palatine** and **greater palatine arteries**. * *Note: The **Ascending Pharyngeal Artery** (from ECA) also contributes to the supply.* ### **NEET-PG High-Yield Pearls** 1. **Main Source:** The **tonsillar branch of the facial artery** is the principal artery supplying the tonsil. It pierces the superior constrictor muscle to reach the lower pole. 2. **Venous Drainage:** Blood drains into the **paratonsillar vein** (external palatine vein), which then drains into the pharyngeal venous plexus. 3. **Clinical Significance:** The paratonsillar vein is the most common source of **primary hemorrhage** during a tonsillectomy. 4. **Nerve Supply:** Primarily by the **glossopharyngeal nerve (CN IX)** via the tonsillar plexus. This explains "referred otalgia" (ear pain) during tonsillitis or post-tonsillectomy.

Question 697: Lymphoid tissue called Waldeyer's ring is situated in which location?

A. Nasopharynx
B. Oropharynx
C. Both nasopharynx and oropharynx (Correct Answer)
D. Base of tongue

Explanation: PH8B9L8B9L **Waldeyer’s Ring** is a circular arrangement of lymphoid tissue located at the entrance of the aerodigestive tract. It serves as the first line of defense against inhaled or ingested pathogens. **Why Option C is correct:** The ring is not confined to a single anatomical space but spans across both the **nasopharynx** and the **oropharynx**. It is composed of four main sets of tonsils: 1. **Pharyngeal tonsil (Adenoids):** Located in the roof and posterior wall of the **nasopharynx**. 2. **Tubal tonsils:** Located around the opening of the Eustachian tube in the **nasopharynx**. 3. **Palatine tonsils:** Located in the tonsillar fossa between the palatoglossal and palatopharyngeal arches in the **oropharynx**. 4. **Lingual tonsils:** Located on the posterior one-third (base) of the tongue in the **oropharynx**. **Why other options are incorrect:** * **Options A & B:** These are partially correct but incomplete. The ring is a continuous functional unit that bridges both regions. * **Option D:** The base of the tongue contains the lingual tonsils, which are only one component of the entire ring. **High-Yield NEET-PG Pearls:** * **Epithelium:** The palatine tonsils are lined by **non-keratinized stratified squamous epithelium**, whereas the adenoids are lined by **ciliated pseudostratified columnar epithelium** (respiratory epithelium). * **Clinical Correlation:** Hypertrophy of the pharyngeal tonsils (adenoids) can lead to mouth breathing and "adenoid facies." * **Lymphatic Drainage:** The entire ring primarily drains into the **jugulodigastric nodes** (the "tonsillar node").

Question 698: General sensation to the posterior one-third of the tongue is mediated by which nerve?

A. Hypoglossal nerve
B. Vagus nerve
C. Glossopharyngeal nerve (Correct Answer)
D. Lingual nerve

Explanation: The tongue has a complex nerve supply derived from its embryological origins. The correct answer is the **Glossopharyngeal nerve (CN IX)**. ### 1. Why Glossopharyngeal Nerve is Correct The tongue is divided into the anterior two-thirds and the posterior one-third by the sulcus terminalis. The **posterior one-third** develops from the third pharyngeal arch. The nerve of the third arch is the Glossopharyngeal nerve; therefore, it provides **both general sensation** (touch, pain, temperature) and **special sensation** (taste) to this region [1]. ### 2. Why Other Options are Incorrect * **Hypoglossal nerve (CN XII):** This is the motor nerve for all intrinsic and extrinsic muscles of the tongue (except the Palatoglossus). It does not carry sensory fibers. * **Vagus nerve (CN X):** Through the internal laryngeal branch, it carries both general and special sensation from the **extreme posterior part** (vallecula and epiglottis), not the main posterior one-third [1]. * **Lingual nerve:** A branch of the Mandibular nerve (V3), it carries **general sensation** from the **anterior two-thirds** of the tongue only. ### 3. High-Yield Clinical Pearls for NEET-PG * **Anterior 2/3 Sensory:** General sensation via Lingual nerve (V3); Taste via Chorda tympani (branch of Facial nerve, CN VII). * **Posterior 1/3 Sensory:** Both general and taste sensations are via the Glossopharyngeal nerve (CN IX) [1]. * **Gag Reflex:** The Glossopharyngeal nerve (CN IX) forms the **afferent** (sensory) limb, while the Vagus nerve (CN X) forms the **efferent** (motor) limb. * **Muscle Exception:** All tongue muscles are supplied by CN XII except the **Palatoglossus**, which is supplied by the Pharyngeal plexus (CN X).

Question 699: The tonsillar fossa is bounded anteriorly by which structure?

A. Pharyngobasilar fascia
B. Palatopharyngeal fold
C. Buccopharyngeal fascia
D. Palatoglossal fold (Correct Answer)

Explanation: ### Explanation The **tonsillar fossa** (or tonsillar sinus) is the depression located in the lateral wall of the oropharynx that houses the palatine tonsil. Understanding its boundaries is high-yield for NEET-PG, as it defines the surgical landscape for tonsillectomy. **1. Why the Correct Answer is Right:** The tonsillar fossa is situated between two mucosal folds formed by underlying muscles: * **Anterior Boundary:** The **Palatoglossal fold** (formed by the palatoglossus muscle). This is the "anterior pillar" of the fauces. * **Posterior Boundary:** The **Palatopharyngeal fold** (formed by the palatopharyngeus muscle), also known as the "posterior pillar." * **Apex:** Formed by the soft palate where the two folds meet. **2. Analysis of Incorrect Options:** * **B. Palatopharyngeal fold:** This forms the **posterior** boundary of the tonsillar fossa, not the anterior. * **A & C. Pharyngobasilar and Buccopharyngeal Fascia:** These structures form part of the **lateral wall (floor)** of the tonsillar fossa. The tonsil rests on the pharyngobasilar fascia, which covers the superior constrictor muscle. The buccopharyngeal fascia lies even more externally, covering the outer surface of the constrictor muscles. **3. Clinical Pearls for NEET-PG:** * **Tonsillar Bed:** The floor of the fossa is formed primarily by the **Superior Constrictor muscle** and the **Styloglossus muscle**. * **Vascularity:** The main artery of the tonsil is the **Tonsillar branch of the Facial Artery**. * **Nerve Supply:** The **Glossopharyngeal nerve (CN IX)** lies in the bed of the tonsil and provides sensory innervation. Injury to this nerve during surgery can lead to referred ear pain (via the tympanic branch/Jacobson’s nerve). * **Bleeding:** The **Paratonsillar vein** (External Palatine vein) is the most common cause of primary hemorrhage during tonsillectomy.

Question 700: All of the following structures pass through the optic foramen except?

A. Optic nerve
B. Ophthalmic artery
C. Oculomotor nerve (Correct Answer)
D. Dura mater

Explanation: The **optic canal** (optic foramen) is a short passage in the **lesser wing of the sphenoid bone** that connects the middle cranial fossa to the apex of the orbit. ### Why Oculomotor Nerve is the Correct Answer: The **Oculomotor nerve (CN III)** does not pass through the optic canal. Instead, it enters the orbit through the **Superior Orbital Fissure (SOF)**. Specifically, both its superior and inferior divisions pass through the SOF within the common tendinous ring (Annulus of Zinn). ### Explanation of Incorrect Options: * **Optic Nerve (CN II):** This is the primary structure of the optic canal. It carries visual information from the retina to the brain. * **Ophthalmic Artery:** A branch of the internal carotid artery, it enters the orbit through the optic canal, positioned inferolateral to the optic nerve. * **Dura Mater:** The optic nerve is an outgrowth of the diencephalon and is therefore encased in the three layers of meninges (dura, arachnoid, and pia mater). These layers, along with the subarachnoid space containing CSF, accompany the nerve through the canal. ### NEET-PG High-Yield Pearls: 1. **Contents of Optic Canal:** Optic nerve, Ophthalmic artery, and Meningeal sheaths (with subarachnoid space). 2. **Clinical Correlation:** Because the subarachnoid space extends around the optic nerve, increased intracranial pressure (ICP) can be transmitted to the back of the eye, leading to **papilledema**. 3. **Superior Orbital Fissure (SOF) Contents:** * *Outside the Tendinous Ring:* Lacrimal, Frontal, and Trochlear (IV) nerves; Superior ophthalmic vein. * *Inside the Tendinous Ring:* Superior and Inferior divisions of Oculomotor (III), Abducens (VI), and Nasociliary nerves.

Practice by Chapter

Skull and Facial Bones

Practice Questions

Scalp and Facial Muscles

Practice Questions

Dural Venous Sinuses

Practice Questions

Cranial Cavity

Practice Questions

Orbit and Contents

Practice Questions

Temporal and Infratemporal Regions

Practice Questions

Pterygopalatine Fossa

Practice Questions

Oral Cavity

Practice Questions

Paranasal Sinuses

Practice Questions

Applied Anatomy and Clinical Correlations

Practice Questions

Want unlimited practice?

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

Start For Free

Head — MCQs

Head — MCQs

On this page

Practice by Chapter

Want unlimited practice?