Head Practice Questions

Q: Mandibular division of trigeminal nerve passes through which of the following? (AIIMS May 2018)

D. ***D*** - The label 'D' points to the **foramen ovale**, which is the opening through which the **mandibular division of the trigeminal nerve (V3)** exits the middle cranial fossa. - The foramen ovale also transmits the **accessory meningeal artery**, **lesser petrosal nerve**, and the **emissary veins**. *A* - The label 'A' points to the **foramen rotundum**, which is primarily for the passage of the **maxillary division of the trigeminal nerve (V2)**. - The foramen rotundum is distinct from the foramen ovale and is located more anterior and medial. *B* - The label 'B' points to the **foramen spinosum**, which allows the passage of the **middle meningeal artery** and the **nervus spinosus (meningeal branch of V3)**. - While it transmits a branch of V3, it is not the main exit point for the entire mandibular division. *C* - The label 'C' points to the **foramen lacerum**, which is occupied by **cartilage** in vivo and primarily traversed by the **internal carotid artery** and its accompanying sympathetic plexus passing superiorly to it. - No major cranial nerves pass completely through it; instead, some nerves (like the greater petrosal nerve) pass over its superior surface or exit through associated canals.

Q: Which nerve passes through the structure shown? (Recent NEET Pattern 2019)

Inferior alveolar nerve. ***Inferior alveolar nerve*** - The image points to the **mandibular foramen**, an opening on the medial surface of the mandibular ramus. - The **inferior alveolar nerve** enters the mandible through this foramen to supply sensation to the mandibular teeth. *Lingual nerve* - The **lingual nerve** typically runs anterior to the inferior alveolar nerve in the infratemporal fossa but does not pass through the mandibular foramen. - It supplies general sensation and taste to the anterior two-thirds of the tongue. *Buccal nerve* - The **buccal nerve** passes between the two heads of the lateral pterygoid muscle and supplies sensation to the buccal mucosa and gingiva, not traveling within the mandible. - It arises from the anterior division of the mandibular nerve. *Hypoglossal nerve* - The **hypoglossal nerve (CN XII)** is a motor nerve for the tongue muscles and is located entirely outside the mandible. - It exits the skull through the hypoglossal canal and runs in the neck and floor of the mouth.

Q: What is the action of the muscle marked in the given image?

Elevation. ***Elevation*** - The image shows a coronal section of the head, and the arrow points to the **temporalis muscle**, which is one of the primary muscles of mastication. - The main action of the temporalis muscle is to **elevate the mandible**, closing the mouth. - The **anterior and middle fibers** particularly produce elevation. *Depression* - Depression of the mandible is primarily performed by the **lateral pterygoid muscle** and the suprahyoid muscles (e.g., digastric, geniohyoid). - The temporalis muscle's fiber orientation is not consistent with mandibular depression. *Protraction* - **Protraction** (protrusion) of the mandible is primarily carried out by the **lateral pterygoid muscles** (bilateral contraction). - The temporalis muscle does not contribute significantly to protraction. *Retraction* - **Retraction** of the mandible is indeed performed by the **posterior fibers of the temporalis muscle**. - However, since the question asks about the action of the muscle as shown in the image (likely showing the entire muscle or its anterior portion), and the **primary and most prominent action** of the temporalis as a whole is **elevation**, this is the best answer.

Q: The area of external auditory canal marked as ' $X$ ' is innervated by which nerve?

Arnold nerve. ***Arnold nerve*** - The **Arnold's nerve**, also known as the **auricular branch of the vagus nerve (CN X)**, innervates the posterior inferior part of the external auditory canal and a portion of the concha. - Stimulation of this nerve can elicit the "ear-cough reflex" (Aristotle's reflex) or cause syncope in susceptible individuals. *Facial nerve* - The facial nerve (CN VII) primarily provides **motor innervation** to the muscles of facial expression. - While it has a small sensory component (nervus intermedius) that supplies taste to the anterior two-thirds of the tongue and a small area of the pinna, it does not significantly innervate the external auditory canal. *Auriculotemporal nerve* - The **auriculotemporal nerve** is a branch of the **mandibular nerve (V3)**, which is part of the trigeminal nerve (CN V). - It primarily innervates the skin of the temporal region, the external auditory meatus (anterior and superior aspects), and the temporomandibular joint, but it is not the primary innervation for the area marked 'X' which is typically posteroinferior. *Lesser occipital nerve* - The lesser occipital nerve is a branch of the **cervical plexus**. - It provides **cutaneous sensation** to the skin over the mastoid process and the upper part of the auricle, not the external auditory canal.

Q: Which of the following nerve supplies the area of pinna marked as X?

Lesser occipital nerve. ***Lesser occipital nerve*** - The **lesser occipital nerve** (C2, C3) primarily supplies the skin of the **cranial surface of the auricle's upper half** and the adjacent scalp, which corresponds to the area marked as X. - This nerve is a branch of the **cervical plexus** and provides sensory innervation to this posterior-superior part of the pinna. *Arnold's nerve* - **Arnold's nerve** (auricular branch of the vagus nerve) supplies the skin of the **concha**, tragus, and external auditory meatus. - Stimulation of this nerve can cause the **cough reflex** or **syncopal episodes** (vasovagal syncope). *Auriculotemporal nerve* - The **auriculotemporal nerve** (a branch of the mandibular nerve, V3) innervates the **anterior and superior parts of the external ear**, including the tragus and helix. - It also provides sensory innervation to the skin of the temple and secretomotor fibers to the **parotid gland**. *Greater occipital nerve* - The **greater occipital nerve** (C2) primarily supplies the skin of the **posterior scalp** up to the vertex. - It does not significantly contribute to the sensory innervation of the pinna itself, though it is located in the nearby posterior neck region.

Q: The X marking shows:

Torus tubarius. ***Torus tubarius*** - The X marking points to a prominent mucosal elevation in the nasopharynx formed by the **cartilaginous end of the Eustachian tube**. - This structure is known as the **torus tubarius** and is a key landmark in the lateral wall of the nasopharynx. *Rathke's pouch* - **Rathke's pouch** is an embryonic invagination of the stomodeum that gives rise to the anterior pituitary gland. - It is located superior to the nasopharynx, not within its lateral wall as shown by the X marking. *Digastric ridge* - The **digastric ridge** is a term not typically used in anatomical descriptions of the nasopharynx or its immediate vicinity. - The digastric muscle is located in the neck, inferior to the structures depicted. *Tegmen plate* - The **tegmen tympani** is a thin plate of bone forming the roof of the tympanic cavity (middle ear). - This structure is part of the temporal bone and is located superior to the nasopharynx, not directly within its lumen as indicated.

Q: In a patient of carcinoma tongue, the infiltration of which muscle causes ankyloglossia ?

Genioglossus muscle. ***Genioglossus muscle*** - Infiltration of the **genioglossus muscle** by carcinoma of the tongue restricts tongue protrusion and movement, functionally mimicking **ankyloglossia** [1]. - The genioglossus is the **primary protrusor** of the tongue, originating from the mental spine of the mandible and inserting into the entire length of the tongue. - When infiltrated by tumor, it causes **inability to protrude the tongue** beyond the lower incisor teeth and deviation toward the affected side [1]. - Though true ankyloglossia is a congenital condition involving the lingual frenulum, this term is used clinically to describe **acquired restriction of tongue mobility**. *Palatoglossus muscle* - The palatoglossus muscle primarily **elevates the posterior tongue** and assists in closing the oropharyngeal isthmus. - Its infiltration would affect **swallowing and palatine arch function** rather than tongue protrusion. - Not the primary cause of restricted tongue protrusion seen in this clinical scenario. *Styloglossus muscle* - The styloglossus muscle **retracts and elevates the sides of the tongue**. - Its involvement would impair retraction and lateral movements but would **not restrict protrusion**, which is the hallmark of ankyloglossia. *Mylohyoid muscle* - The mylohyoid forms the **muscular floor of the mouth** and elevates the hyoid bone and tongue during swallowing. - It is not an intrinsic tongue muscle; infiltration would cause **floor of mouth issues** and dysphagia rather than specific restriction of tongue protrusion.

Q: All of the following cranial nerves pass through the jugular foramen except :

Hypoglossal. ***Hypoglossal*** - The **hypoglossal nerve (CN XII)** exits the skull through the **hypoglossal canal**, not the jugular foramen. - Its primary function is to innervate the intrinsic and extrinsic muscles of the **tongue**. *Vagus* - The **vagus nerve (CN X)** is one of the three cranial nerves that traverse the **jugular foramen**. - It has extensive innervation, including parasympathetic supply to the **heart, lungs, and most of the gastrointestinal tract**. *Glossopharyngeal* - The **glossopharyngeal nerve (CN IX)** exits the skull via the **jugular foramen**. - It is responsible for **taste sensation** from the posterior one-third of the tongue and motor innervation to the **stylopharyngeus muscle**. *Spinal accessory* - The **spinal accessory nerve (CN XI)** passes through the **jugular foramen** after entering the cranial cavity through the foramen magnum. - It innervate the **sternocleidomastoid** and **trapezius muscles**, responsible for head and shoulder movements.

Q: A fracture of the middle cranial fossa may result in an injury of the

Sixth cranial nerve. ***Sixth cranial nerve*** - The **abducens nerve (CN VI)** passes through the **Dorello's canal (or petroclival ligament)**, located in the vicinity of the middle cranial fossa. - Fractures in this region can lead to **stretching or compression** of the abducens nerve, resulting in **lateral rectus palsy** and *diplopia*. *Tenth cranial nerve* - The **vagus nerve (CN X)** exits the skull via the **jugular foramen**, located in the **posterior cranial fossa**. - Injury to this nerve is less likely with a fracture specifically confined to the middle cranial fossa. *Eighth cranial nerve* - The **vestibulocochlear nerve (CN VIII)** courses through the **internal auditory meatus** in the **petrous part of the temporal bone**, which is part of the posterior cranial fossa. - While acoustic trauma or petrous bone fractures can affect it, it's not a primary concern with general middle cranial fossa fractures. *Eleventh cranial nerve* - The **spinal accessory nerve (CN XI)** exits the skull through the **jugular foramen**, similar to the vagus nerve, placing it in the **posterior cranial fossa**. - Damage to this nerve would primarily cause weakness in the **sternocleidomastoid** and **trapezius muscles**, and is not typically associated with isolated middle cranial fossa fractures.

Question 1

Mandibular division of trigeminal nerve passes through which of the following? (AIIMS May 2018)

Accepted Answer

D

Answer

A

Answer

B

Answer

C

Question 2

Which nerve passes through the structure shown? (Recent NEET Pattern 2019)

Accepted Answer

Inferior alveolar nerve

Answer

Lingual nerve

Answer

Buccal nerve

Answer

Hypoglossal nerve

Question 3

What is the action of the muscle marked in the given image?

Accepted Answer

Elevation

Answer

Depression

Answer

Protraction

Answer

Retraction

Question 4

All are correct about the part marked as $X$ and $Y$ except:

Accepted Answer

$X$ is utricle and has anterior upward slope of 30 degrees

Answer

$Y$ is ductus reuniens

Answer

$Y$ connects utricle to cochlear duct

Answer

$X$ is utricle and receives 5 openings of three semicircular canals

Question 5

The area of external auditory canal marked as ' $X$ ' is innervated by which nerve?

Accepted Answer

Arnold nerve

Answer

Facial nerve

Answer

Auriculotemporal nerve

Answer

Lesser occipital nerve

Question 6

Which of the following nerve supplies the area of pinna marked as X?

Accepted Answer

Lesser occipital nerve

Answer

Arnold's nerve

Answer

Auriculotemporal nerve

Answer

Greater occipital nerve

Question 7

The X marking shows:

Accepted Answer

Torus tubarius

Answer

Rathke's pouch

Answer

Digastric ridge

Answer

Tegmen plate

Question 8

In a patient of carcinoma tongue, the infiltration of which muscle causes ankyloglossia ?

Accepted Answer

Genioglossus muscle

Answer

Palatoglossus muscle

Answer

Styloglossus muscle

Answer

Mylohyoid muscle

Question 9

All of the following cranial nerves pass through the jugular foramen except :

Accepted Answer

Hypoglossal

Answer

Vagus

Answer

Glossopharyngeal

Answer

Spinal accessory

Question 10

A fracture of the middle cranial fossa may result in an injury of the

Accepted Answer

Sixth cranial nerve

Answer

Tenth cranial nerve

Answer

Eighth cranial nerve

Answer

Eleventh cranial nerve

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