Head Practice Questions

Q: Which nerve supplies the area of nose marked as $X$ ?

***The correct answer depends on the marked area X in the image*** The external nose receives sensory innervation from branches of the **trigeminal nerve (CN V)**: **From Ophthalmic division (V1):** - **Infratrochlear nerve**: Supplies the lateral aspect and tip of the nose - **External nasal nerve** (terminal branch of anterior ethmoidal nerve): Supplies the dorsum and tip of the nose **From Maxillary division (V2):** - **Infraorbital nerve**: Supplies the lateral aspect of the nose and ala - **Nasopalatine nerve**: Supplies the nasal septum (internal aspect) The correct answer should correspond to the anatomical area marked as X in the provided image. Each region of the nose has distinct innervation patterns that are clinically relevant for local anesthesia procedures.

Q: Safety muscle of the tongue is:

A. ***A - Genioglossus muscle*** - The **genioglossus muscle** is the "safety muscle" of the tongue because it **prevents the tongue from falling backward and obstructing the airway**. - It originates from the **superior genial tubercle** of the mandible and fans out into the tongue, with its primary action being **tongue protrusion**. - **Clinical significance**: In unconscious patients, loss of genioglossus tone allows the tongue to fall back, causing airway obstruction. This is why the **jaw thrust maneuver** works—it pulls the mandible (and attached genioglossus) forward. *B - Mylohyoid muscle* - The mylohyoid forms the **floor of the mouth** (diaphragma oris). - Its primary function is **elevating the hyoid bone and floor of the mouth** during swallowing and speaking. - It does not directly prevent airway obstruction by the tongue. *C - Styloglossus muscle* - The styloglossus is an **extrinsic muscle** that retracts and elevates the tongue. - It acts as an **antagonist to the genioglossus**, pulling the tongue backward and upward. - It does not have a protective role in maintaining airway patency. *D - Palatoglossus muscle* - The palatoglossus elevates the **posterior part of the tongue** and depresses the soft palate. - It helps **seal off the oral cavity from the pharynx** during swallowing (forming the palatoglossal arch/anterior pillar of fauces). - It does not prevent tongue from falling back into the airway.

Q: Which of the color-marked muscles shown below is the antagonist muscle to superior rectus?

Blue. ***Blue*** - The blue structure represents the **inferior rectus muscle**, which is responsible for **depression** and some adduction/extorsion of the eye. - As the superior rectus primarily performs **elevation** of the eye, the inferior rectus acts as its direct antagonist. *Green* - The green structure represents the **medial rectus muscle**, which primarily causes **adduction** (moving the eye inward). - Its antagonist is the lateral rectus, not the superior rectus. *Purple* - The purple structure represents the **levator palpebrae superioris**, a muscle responsible for **elevating the upper eyelid**. - It does not directly move the eyeball, so it cannot be an antagonist to the superior rectus, which moves the eye. *Yellow* - The yellow structure is likely the **lacrimal gland**, an exocrine gland responsible for producing **tears**. - It is not a muscle and therefore cannot act as an antagonist to any extraocular muscle.

Q: The following structure marked as $X$ is?

Torcular Herophili. ***Torcular herophili*** - The image points to the confluence of sinuses, also known as the **torcular herophili**, which is the meeting point of the superior sagittal, straight, occipital, and transverse sinuses. - It is located at the **internal occipital protuberance**, a key anatomical landmark for cerebral venous drainage. *Vein of Galen* - The **great cerebral vein of Galen** is an unpaired deep cerebral vein formed by the union of the two internal cerebral veins and the two basal veins of Rosenthal. - It drains into the **straight sinus** and is located more anterior and inferior to the marked structure. *Basal vein of Rosenthal* - The **basal vein of Rosenthal** is a deep cerebral vein that originates near the anterior perforated substance and drains into the great cerebral vein of Galen. - It is located deep within the brain and is not typically visible in this superficial view of the major dural sinuses. *Straight sinus* - The **straight sinus** (also known as the tentorial sinus) is a dural venous sinus that drains the deep brain structures. - It merges with the superior sagittal sinus at the torcular herophili, but the arrow points specifically to the **confluence** of these sinuses rather than the straight sinus itself, which connects more anteriorly.

Q: Identify the structure marked by the arrow in this skull base image:

Vertebral artery. ***Vertebral artery*** - The arrow indicates the **vertebral artery** as it ascends through the **foramen magnum** into the posterior fossa, appearing as a prominent paired vascular structure lateral to the **medulla oblongata**. - In skull base imaging, vertebral arteries appear as **cylindrical structures** running alongside the brainstem, distinguishable from nerves by their **larger caliber** and **bilateral symmetry** at the craniovertebral junction. *Spinal accessory nerve* - The **spinal accessory nerve (CN XI)** has a much **smaller diameter** than the indicated structure and would appear as a thin nerve bundle coursing toward the **jugular foramen**. - It enters the skull through the foramen magnum but quickly turns laterally toward the **jugular foramen**, not maintaining the vertical course shown by the arrow. *Labyrinthine artery* - The **labyrinthine artery** is a **small branch** of the AICA that enters the **internal acoustic meatus** to supply the inner ear, too small to be clearly visible at this magnification. - It would be located more **anterolaterally** near the cerebellopontine angle, not in the **midline posterior fossa** location indicated by the arrow. *Abducens nerve* - The **abducens nerve (CN VI)** emerges from the **pontomedullary junction** and travels anteriorly through the **cavernous sinus**, located much more **superiorly and anteriorly** than the marked structure. - It would appear as a **thin nerve** rather than the **robust vascular structure** indicated, and would not be visible at the **foramen magnum level**.

Q: Which of the following structures will help in opening of jaw?

C. ***C*** - Structure C represents the **lateral pterygoid muscle**, which is the primary muscle responsible for **opening the jaw (depression of the mandible)**, as well as protrusion and contralateral excursion. - It is the only muscle of mastication that actively participates in jaw opening. *A* - Structure A appears to be the **medial pterygoid muscle**, which is primarily involved in **elevation of the mandible** (jaw closing) and side-to-side movements. - Its action is antagonistic to jaw opening. *B* - Structure B likely represents the **masseter muscle**, a powerful muscle of mastication that primarily functions to **elevate the mandible** and close the jaw. - It is a strong jaw closer, not an opener. *D* - Structure D points to the **temporalis muscle**, another major muscle of mastication that is responsible for **elevating and retracting the mandible** (closing the jaw). - Its primary actions are in jaw closing, not opening.

Q: What is the function of the muscle marked in the cut section shown below? (AIIMS May 2018)

Depression. ***Depression*** - The image shows the **lateral pterygoid muscle** in a transverse section of the head. The **inferior head** of this muscle assists in **mandibular depression** (mouth opening) when both sides contract together. - While the **primary functions** of the lateral pterygoid are **protrusion** and **lateral excursion** of the mandible, among the given options, **depression is the only function this muscle actually performs**. - The lateral pterygoid does **NOT perform elevation or retraction**, making depression the **only anatomically correct answer** from the choices provided. *Elevation* - The lateral pterygoid muscle does **NOT elevate** the mandible - this is anatomically incorrect. - **Primary elevators** of the mandible are the **masseter**, **temporalis**, and **medial pterygoid muscles** (all supplied by the mandibular division of the trigeminal nerve). *Retraction* - The lateral pterygoid muscle does **NOT retract** the mandible - it actually **protrudes** it, which is the **opposite of retraction**. - **Mandibular retraction** is primarily performed by the **posterior fibers of the temporalis muscle** and the **deep fibers of the masseter**. *All of the above* - This option is incorrect because the lateral pterygoid does **NOT perform elevation or retraction**. - The muscle's **primary functions** are **protrusion** (forward movement) and **lateral excursion** (side-to-side movement), with **assistive role in depression** (mouth opening) when both inferior heads contract simultaneously.

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.

Question 1

Which nerve supplies the area of nose marked as $X$ ?

Question 2

Safety muscle of the tongue is:

Accepted Answer

A

Answer

B

Answer

C

Answer

D

Question 3

Which of the color-marked muscles shown below is the antagonist muscle to superior rectus?

Accepted Answer

Blue

Answer

Green

Answer

Purple

Answer

Yellow

Question 4

The following structure marked as $X$ is?

Accepted Answer

Torcular Herophili

Answer

Vein of Galen

Answer

Basal vein of Rosenthal

Answer

Straight Sinus

Question 5

Identify the structure marked by the arrow in this skull base image:

Accepted Answer

Vertebral artery

Answer

Spinal accessory nerve

Answer

Labyrinthine artery

Answer

Abducens nerve

Question 6

Which of the following structures will help in opening of jaw?

Accepted Answer

C

Answer

A

Answer

B

Answer

D

Question 7

What is the function of the muscle marked in the cut section shown below? (AIIMS May 2018)

Accepted Answer

Depression

Answer

Elevation

Answer

Retraction

Answer

All of the above

Question 8

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

Accepted Answer

D

Answer

A

Answer

B

Answer

C

Question 9

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 10

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

Accepted Answer

Elevation

Answer

Depression

Answer

Protraction

Answer

Retraction

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