Head Practice Questions

Q: Which of the following muscles is considered an accessory muscle of mastication?

Buccinator. ### Explanation **Correct Answer: C. Buccinator** The **Buccinator** is anatomically classified as a muscle of facial expression (innervated by the Facial nerve, CN VII), but it is functionally considered an **accessory muscle of mastication**. **Why it is the correct answer:** While the primary muscles of mastication (Masseter, Temporalis, Medial, and Lateral Pterygoids) move the mandible, the Buccinator plays a crucial role during the chewing process. It flattens the cheek against the teeth, preventing food from accumulating in the oral vestibule and pushing the bolus back between the occlusal surfaces of the teeth. Without the Buccinator, efficient mastication is impossible as food would constantly get stuck between the gums and cheeks. **Analysis of Incorrect Options:** * **A. Risorius:** A superficial muscle of facial expression that pulls the angle of the mouth laterally (the "grinning" muscle). It has no functional role in chewing. * **B. Orbicularis oris:** A sphincter muscle that closes and protrudes the lips (the "kissing" muscle). While it helps keep the mouth closed during chewing, it does not manipulate the food bolus between the teeth. * **C. Platysma:** A broad, thin sheet of muscle in the neck that depresses the mandible and wrinkles the skin of the lower face; it is not involved in the active process of mastication. **High-Yield Clinical Pearls for NEET-PG:** * **Innervation:** Unlike the primary muscles of mastication (Trigeminal nerve, V3), the Buccinator is supplied by the **buccal branch of the Facial nerve (CN VII)**. * **Structures piercing the Buccinator:** The **Parotid duct (Stensen’s duct)** pierces the buccinator muscle opposite the upper second molar tooth. * **Clinical Sign:** In **Bell’s Palsy** (CN VII palsy), paralysis of the buccinator leads to the accumulation of food in the vestibule of the mouth on the affected side.

Q: In which bone is the inner ear located?

Petrous part of temporal bone. **Explanation:** The **temporal bone** is a complex bone that forms part of the lateral wall and base of the skull. It is divided into four main parts: squamous, mastoid, tympanic, and petrous. [1] The **petrous part of the temporal bone** is a dense, pyramid-shaped wedge located at the base of the skull between the sphenoid and occipital bones. It is the hardest bone in the human body, a property necessary to protect the delicate structures of the **inner ear** (the cochlea for hearing and the vestibular apparatus for balance), as well as the internal auditory meatus. **Analysis of Options:** * **A. Parietal bone:** This forms the bulk of the cranial vault (roof and sides) and does not contain any auditory structures. * **C. Occipital bone:** This forms the back and base of the skull, housing the foramen magnum, but does not contain the inner ear. * **D. Petrous part of squamous bone:** This is anatomically incorrect. The "petrous" and "squamous" are two distinct parts of the temporal bone; there is no petrous part of the squamous bone. **High-Yield Facts for NEET-PG:** * **Internal Auditory Meatus:** Located in the petrous part, it transmits the Facial nerve (VII), Vestibulocochlear nerve (VIII), and the labyrinthine artery. * **Carotid Canal:** The internal carotid artery passes through the petrous temporal bone. * **Clinical Correlation:** Fractures of the petrous temporal bone (longitudinal or transverse) can lead to CSF otorrhea, facial nerve palsy, or sensorineural hearing loss. * **Hardness:** The petrous part is often referred to as the "petrous pyramid" due to its density and shape.

Q: Gag reflex is lost due to paralysis of which cranial nerve?

IX nerve. The **Gag Reflex** (Pharyngeal Reflex) is a protective mechanism that prevents foreign objects from entering the airway. It is mediated by a reflex arc involving two specific cranial nerves: 1. **Afferent Limb (Sensory):** **Glossopharyngeal Nerve (CN IX)**. It carries sensory impulses from the oropharynx and the posterior one-third of the tongue to the brainstem. 2. **Efferent Limb (Motor):** **Vagus Nerve (CN X)**. It carries motor impulses to the pharyngeal constrictor muscles, leading to contraction. Since the **Glossopharyngeal nerve (CN IX)** is responsible for the sensory initiation of the reflex, its paralysis results in the loss of the gag reflex on the affected side. ### Analysis of Options: * **Option A (V nerve):** The Trigeminal nerve provides general sensation to the anterior two-thirds of the tongue and face, but it is not part of the gag reflex arc. * **Option B (VII nerve):** The Facial nerve is responsible for taste (anterior 2/3 of the tongue) and muscles of facial expression. It does not mediate the gag reflex. * **Option D (XII nerve):** The Hypoglossal nerve provides motor supply to the intrinsic and extrinsic muscles of the tongue. Damage causes tongue deviation but does not abolish the gag reflex. ### High-Yield Clinical Pearls for NEET-PG: * **Testing:** The reflex is tested by touching the posterior pharyngeal wall or tonsillar pillar. * **Glossopharyngeal Neuralgia:** Characterized by paroxysmal pain triggered by swallowing or touching the back of the throat. * **Jugular Foramen Syndrome:** Involves CN IX, X, and XI; a lesion here will result in a lost gag reflex, hoarseness, and weakness of the trapezius/sternocleidomastoid muscles. * **Uvula Deviation:** In a vagus nerve (CN X) lesion, the uvula deviates toward the **healthy** side.

Q: Parasympathetic postganglionic fibres are carried by which nerve?

Auriculotemporal nerve. The Auriculotemporal nerve (a branch of the Mandibular nerve, V3) is the correct answer because it serves as the final vehicle for postganglionic parasympathetic fibers destined for the parotid gland. The pathway is as follows: Preganglionic fibers originate in the inferior salivatory nucleus, travel via the glossopharyngeal nerve (IX) and the lesser petrosal nerve to synapse in the otic ganglion. From there, the postganglionic fibers "hitchhike" along the auriculotemporal nerve to reach the parotid gland to stimulate secretion [1]. Analysis of Incorrect Options: * Long ciliary nerves: These carry sympathetic postganglionic fibers (for pupillary dilation) and sensory fibers from the nasociliary nerve to the eyeball. * Greater petrosal nerve: This carries preganglionic parasympathetic fibers from the facial nerve (VII) to the pterygopalatine ganglion. * Deep petrosal nerve: This carries sympathetic postganglionic fibers from the internal carotid plexus to join the greater petrosal nerve, forming the nerve of the pterygoid canal (Vidian nerve). High-Yield NEET-PG Pearls: * Frey’s Syndrome: Damage to the auriculotemporal nerve during parotid surgery can lead to "gustatory sweating," where regenerating parasympathetic fibers mistakenly innervate sweat glands in the skin. * The "Hitchhiker" Rule: In the head and neck, parasympathetic fibers always use branches of the Trigeminal nerve (V) to reach their final destination. * Otic Ganglion: Remember the mnemonic L-O-A-P (Lesser petrosal – Otic ganglion – Auriculotemporal nerve – Parotid).

Q: Which of the following sutures closes earliest?

Metopic suture. **Explanation:** The **metopic (frontal) suture** is the correct answer because it is the only cranial suture that normally undergoes physiological obliteration during early childhood [2]. While most other sutures remain open until the third or fourth decade of life to allow for brain expansion, the metopic suture begins to close at **2 years of age** and is typically completely fused by **7 to 8 years**. In about 8% of the population, it persists into adulthood (metopism). **Analysis of Options:** * **Metopic Suture (Correct):** Closes between 2–8 years [2]. Early pathological closure (craniosynostosis) of this suture leads to **Trigonocephaly** (a wedge-shaped forehead) [1]. * **Sagittal Suture:** This is the most common suture involved in craniosynostosis (Scaphocephaly), but physiologically, it starts closing around **age 22** and completes by age 35 [2]. * **Coronal Suture:** Begins closure around **age 24** and completes by age 38–41 [2]. * **Lambdoid Suture:** Begins closure around **age 26** and completes by age 42–47 [2]. **Clinical Pearls for NEET-PG:** 1. **Sequence of Closure:** Metopic → Sagittal → Coronal → Lambdoid (M-S-C-L). 2. **Fontanelles:** Do not confuse sutures with fontanelles. The **Posterior fontanelle** closes first (2–3 months), while the **Anterior fontanelle** (Bregma) closes last (18–24 months). 3. **Virchow’s Law:** Premature suture fusion results in inhibited growth perpendicular to the suture and compensatory growth parallel to it.

Q: Which part of orbicularis oculi is known as Horner's muscle?

Lacrimal. The **Orbicularis oculi** is the sphincter muscle of the eye, supplied by the Facial nerve (CN VII). It consists of three main parts: orbital, palpebral, and lacrimal. **Why Lacrimal is correct:** The **Lacrimal part** (also known as **Horner’s muscle** or *pars lacrimalis*) originates from the posterior lacrimal crest and the fascia covering the lacrimal sac. It passes behind the lacrimal sac and inserts into the tarsi of the eyelids. Its primary function is to dilate the lacrimal sac and draw the eyelids medially, creating a "pumping" action that facilitates the drainage of tears into the nasolacrimal duct. **Analysis of Incorrect Options:** * **Orbital part:** This is the peripheral part of the muscle used for forceful closure of the eyes (e.g., winking or protecting against bright light). * **Temporal part:** There is no "temporal part" of the orbicularis oculi; the muscle is divided into orbital, palpebral, and lacrimal portions. * **Muller’s muscle:** Also known as the superior tarsal muscle, this is a **smooth muscle** innervated by sympathetic fibers. It helps maintain the elevation of the upper eyelid; its paralysis leads to partial ptosis (seen in Horner’s Syndrome). **High-Yield Clinical Pearls for NEET-PG:** * **Riolan’s Muscle:** This refers to the marginal part of the palpebral portion of the orbicularis oculi, located near the lid margin behind the eyelashes. * **Nerve Supply:** All parts of the orbicularis oculi are supplied by the **Temporal and Zygomatic branches of the Facial nerve**. * **Clinical Sign:** Paralysis of the lacrimal part (Horner's muscle) leads to **Epiphora** (overflow of tears) because the lacrimal pump mechanism fails. * **Distinction:** Do not confuse *Horner’s muscle* (Anatomy) with *Horner’s Syndrome* (Clinical triad of miosis, ptosis, and anhidrosis).

Q: Which muscle dilates the palpebral aperture?

Levator palpebrae superioris. **Explanation:** The **palpebral aperture** is the anatomical term for the opening between the eyelids. The width of this aperture is determined by the balance between muscles that close the lids and those that elevate them. **Why Levator Palpebrae Superioris (LPS) is correct:** The LPS is the primary elevator of the upper eyelid. It originates from the lesser wing of the sphenoid and inserts into the tarsal plate and the skin of the upper lid. When it contracts, it pulls the upper eyelid upward, thereby **dilating (opening)** the palpebral aperture. It is supplied by the **Oculomotor nerve (CN III)**. **Analysis of Incorrect Options:** * **Orbicularis oculi:** This is the primary muscle for **closing** the eye (constricting the palpebral aperture). It is supplied by the Facial nerve (CN VII). * **Orbicularis oris:** This is a sphincter muscle surrounding the **mouth**, responsible for closing and puckering the lips. * **Levator labii superioris:** This muscle is located in the mid-face and functions to **elevate the upper lip**, not the eyelid. **High-Yield Clinical Pearls for NEET-PG:** 1. **Müller’s Muscle (Superior Tarsal Muscle):** A sympathetically innervated smooth muscle that assists LPS in maintaining the "wide-eyed" look. 2. **Ptosis:** Drooping of the upper eyelid. It occurs in **3rd Nerve Palsy** (complete ptosis) or **Horner’s Syndrome** (partial ptosis due to loss of sympathetic supply to Müller’s muscle). 3. **Antagonist:** The Orbicularis oculi is the direct antagonist to the LPS. Damage to CN VII (e.g., Bell’s Palsy) results in an inability to close the eye (**Lagophthalmos**).

Question 1

Which of the following muscles is considered an accessory muscle of mastication?

Accepted Answer

Buccinator

Answer

Risorius

Answer

Orbicularis oris

Answer

Platysma

Question 2

A patient presents with epiphora after a fracture of the middle cranial foramen. Which structure's damage is most likely responsible for this symptom?

Accepted Answer

None of the above

Answer

Ciliary ganglion

Answer

Greater palatine nerve

Answer

Infraorbital nerve

Question 3

In which bone is the inner ear located?

Accepted Answer

Petrous part of temporal bone

Answer

Parietal bone

Answer

Occipital bone

Answer

Petrous part of squamous bone

Question 4

Gag reflex is lost due to paralysis of which cranial nerve?

Accepted Answer

IX nerve

Answer

V nerve

Answer

VII nerve

Answer

XII nerve

Question 5

Parasympathetic postganglionic fibres are carried by which nerve?

Accepted Answer

Auriculotemporal nerve

Answer

Long ciliary nerves

Answer

Greater petrosal nerves

Answer

Deep petrosal nerve

Question 6

Which of the following sutures closes earliest?

Accepted Answer

Metopic suture

Answer

Lambdoid suture

Answer

Sagittal suture

Answer

Coronal suture

Question 7

Which of the following statements is true about the tongue?

Accepted Answer

Taste fibers from the anterior two-thirds of the tongue are supplied by the facial nerve.

Answer

Extrinsic and intrinsic muscles of the tongue are supplied by the lingual nerve.

Answer

The posterior one-third of the tongue drains into the submandibular lymph nodes.

Answer

The posterior one-third of the tongue is supplied by the vagus nerve.

Question 8

Which part of orbicularis oculi is known as Horner's muscle?

Accepted Answer

Lacrimal

Answer

Orbital

Answer

Temporal

Answer

Muller's muscle

Question 9

Which of the following statement about the nerve supply of the palate is NOT TRUE?

Accepted Answer

The anterior branch of the pterygopalatine ganglion supplies the soft palate.

Answer

The pharyngeal plexus supplies the muscles of the soft palate.

Answer

The tensor veli palatini is supplied by the mandibular nerve.

Answer

The middle and posterior lesser palatine nerves supply the soft palate and tonsil.

Question 10

Which muscle dilates the palpebral aperture?

Accepted Answer

Levator palpebrae superioris

Answer

Orbicularis oculi

Answer

Orbicularis oris

Answer

Levator labii superioris

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