Head — MCQs

Head Indian Medical PG Practice Questions and MCQs

Question 1231: All of the following arteries are branches of ECA that supply nasal septum except:

A. Facial artery
B. Superior labial artery
C. Anterior ethmoidal artery (Correct Answer)
D. Sphenopalatine artery

Explanation: ***Anterior ethmoidal artery*** - The **anterior ethmoidal artery** is a branch of the **ophthalmic artery**, which itself is a branch of the **internal carotid artery (ICA)**, not the external carotid artery (ECA). - It supplies the **upper anterior nasal septum** and lateral wall of the nasal cavity. *Facial artery* - The **facial artery** is a direct branch of the **external carotid artery (ECA)**. - It contributes to the blood supply of the nasal septum through its septal branches. *Superior labial artery* - The **superior labial artery** is a branch of the **facial artery**, meaning it indirectly originates from the **external carotid artery (ECA)**. - It sends a septal branch to supply the **anterior inferior part of the nasal septum**. *Sphenopalatine artery* - The **sphenopalatine artery** is a direct terminal branch of the **maxillary artery**, which is one of the terminal branches of the **external carotid artery (ECA)**. - It is the major blood supply to the **posterior nasal septum** and lateral wall, forming part of Kesselbach's plexus.

Question 1232: Which vessel is most likely damaged in an extradural (epidural) hemorrhage?

A. Basilar artery
B. Vertebral artery
C. Middle meningeal artery (Correct Answer)
D. Anterior cerebral artery

Explanation: Middle meningeal artery - An extradural (epidural) hemorrhage often results from head trauma, especially to the temporal region, which can cause a fracture across the course of the middle meningeal artery [1]. - This artery runs in a groove on the inner surface of the temporal bone, making it vulnerable to laceration during trauma [1]. Basilar artery - The basilar artery is located at the base of the brainstem and is a common site for strokes, but not typically involved in an extradural hemorrhage. - Damage to the basilar artery usually leads to subarachnoid hemorrhage or ischemic stroke, not an epidural hematoma. Vertebral artery - The vertebral arteries ascend through the cervical vertebrae and join to form the basilar artery, supplying the posterior circulation of the brain. - Damage to these arteries is typically associated with neck trauma or dissection, leading to subarachnoid hemorrhage or ischemia, not an epidural hemorrhage. Anterior cerebral artery - The anterior cerebral artery supplies the frontal lobes and medial aspects of the cerebral hemispheres. - While it can be involved in subarachnoid or intracranial hemorrhages from aneurysm rupture or trauma, it is not the typical source of an epidural hematoma.

Question 1233: Which of the following is the PRIMARY action of the superior oblique muscle?

A. Adduction
B. Intorsion (Correct Answer)
C. Abduction
D. Depression

Explanation: ***Intorsion*** - The **primary action** of the **superior oblique muscle** is **intorsion** (internal rotation), which means rotating the top of the eyeball medially (towards the nose). - This action helps to counteract the **extorsion** caused by the inferior oblique muscle and stabilize the visual field during head tilt. *Depression* - While the superior oblique muscle does contribute to **depression** (moving the eye downwards), this is a **secondary action**, particularly when the eye is in **abduction** [1]. - The **inferior rectus muscle** is the primary depressor of the eye [1]. *Abduction* - The superior oblique has a minor **tertiary action** of **abduction** (moving the eye away from the midline) [1]. - However, the **lateral rectus muscle** is the primary abductor of the eye [1]. *Adduction* - **Adduction** (moving the eye towards the midline) is primarily performed by the **medial rectus muscle** [1]. - The superior oblique muscle does **NOT** contribute to adduction; this is not one of its actions [1].

Question 1234: Which muscle is primarily responsible for opening the Eustachian tube?

A. Stapedius
B. Tensor veli palatini (Correct Answer)
C. Levator veli palatini
D. Tensor tympani

Explanation: ***Tensor veli palatini*** - The **tensor veli palatini muscle** is directly involved in *opening* the **Eustachian tube** during swallowing and yawning. [1] - Its contraction pulls on the lateral wall of the cartilaginous part of the tube, allowing for *equilibration of pressure* between the middle ear and the nasopharynx. [1] *Stapedius* - The **stapedius muscle** is located in the middle ear and is responsible for *stabilizing the stapes*, reducing the transmission of loud sounds to the inner ear. [1] - It plays no direct role in the *opening or closing* of the Eustachian tube. [1] *Levator veli palatini* - The **levator veli palatini muscle** primarily *elevates the soft palate* during swallowing, helping to separate the oral cavity from the nasopharynx. - While it has a minor and indirect effect on the Eustachian tube, it is not the *primary muscle* responsible for its opening. *Tensor tympani* - The **tensor tympani muscle** is also located in the middle ear and functions to *dampen vibrations* of the malleus and stiffen the tympanic membrane in response to loud noises. - It is not involved in the *function or patency* of the Eustachian tube.

Question 1235: Post-tonsillectomy, a patient presents with altered posterior tongue sensation and taste. Which nerve is responsible for these changes, and what are its other functions?

A. Glossopharyngeal; responsible for swallowing and the gag reflex. (Correct Answer)
B. Facial; responsible for facial movements.
C. Hypoglossal; responsible for tongue movements.
D. Vagus; involved in parasympathetic functions in the thorax.

Explanation: ***Correct: Glossopharyngeal; responsible for swallowing and the gag reflex.*** - The **glossopharyngeal nerve (CN IX)** provides general sensation and taste to the posterior one-third of the tongue. Damage during a tonsillectomy can lead to altered sensation and taste in this region [1]. - It also plays a crucial role in the **gag reflex** (afferent limb) and innervates the **stylopharyngeus muscle** for swallowing. *Incorrect: Facial; responsible for facial movements.* - The **facial nerve (CN VII)** is primarily responsible for **facial expression muscles** and taste sensation from the anterior two-thirds of the tongue, not the posterior [1]. - Damage to the facial nerve would manifest as **facial weakness or paralysis**, and potentially altered taste on the anterior tongue. *Incorrect: Hypoglossal; responsible for tongue movements.* - The **hypoglossal nerve (CN XII)** is responsible for the intrinsic and extrinsic muscles of the tongue, controlling **tongue movements** for speech and swallowing. - Damage would result in **tongue deviation** or weakness, not primarily altered sensation or taste. *Incorrect: Vagus; involved in parasympathetic functions in the thorax.* - The **vagus nerve (CN X)** has widespread functions, including innervation of the pharynx, larynx, and major parasympathetic input to thoracic and abdominal organs. - While it contributes to swallowing and sensation around the base of the tongue/epiglottis, it is not the primary mediator of **posterior tongue sensation and taste**.

Question 1236: A patient with a fracture in the middle third of the face would likely have damage to which of the following bones?

A. Mandible
B. Maxilla (Correct Answer)
C. Zygomatic bone
D. Frontal bone

Explanation: ***Maxilla*** - The **maxilla** forms the central part of the **midface**, including the upper jaw, floor of the nose, and lower orbital rim [1]. - Fractures in the middle third of the face, often classified as **Le Fort fractures**, predominantly involve the maxilla. - The maxilla is the **key bone** defining middle third facial fractures in clinical classification [1]. *Mandible* - The **mandible** is the bone of the **lower jaw** and is considered part of the lower third of the face. - Fractures of the mandible would present as damage to the chin and lower jaw region, not the middle third [1]. *Zygomatic bone* - The **zygomatic bone** (cheekbone) is anatomically part of the midface and can be involved in midface trauma. - However, isolated zygomatic fractures are classified separately as **zygomaticomaxillary complex (ZMC)** fractures. - The term "middle third facial fracture" clinically refers primarily to **maxillary fractures**, particularly the Le Fort classification system. *Frontal bone* - The **frontal bone** forms the forehead and the roof of the orbital cavities, placing it in the **upper third of the face**. - Damage to the frontal bone would typically result from trauma to the forehead, not the middle third of the face.

Question 1237: During a dissection, a medical student has difficulty tracing the facial nerve through the parotid gland. What anatomical relationships should they consider to accurately locate this nerve?

A. Deep to the retromandibular vein and external carotid artery
B. Lateral to the mastoid process and medial to the styloid process
C. Superficial to the retromandibular vein and external carotid artery (Correct Answer)
D. Medial to the mastoid process and lateral to the styloid process

Explanation: ***Superficial to the retromandibular vein and external carotid artery*** - The **facial nerve** typically enters the posterior aspect of the **parotid gland** and runs superficially to both the **retromandibular vein** and the **external carotid artery** within the gland. - This anatomical relationship is crucial for surgeons to identify and preserve the facial nerve during a **parotidectomy**, as the nerve splits into its terminal branches here. *Deep to the retromandibular vein and external carotid artery* - This statement is incorrect as the **facial nerve** generally runs **superficial** to these vascular structures within the **parotid gland**. - Placing the nerve deep to these vessels would contradict its typical anatomical course and branching pattern. *Lateral to the mastoid process and medial to the styloid process* - While the **facial nerve** exits the skull through the **stylomastoid foramen**, which is indeed located between the **mastoid process** and the **styloid process**, its course through the parotid gland is described relative to structures within the gland itself. - This description is accurate for the initial exit from the skull, but not for its precise location within the parotid gland relative to major vessels. *Medial to the mastoid process and lateral to the styloid process* - This is an **incorrect** description. The **facial nerve** exits via the **stylomastoid foramen**, which is located **lateral to the styloid process** and **medial to the mastoid process** (not the reverse as stated in this option). - The key anatomical relationships within the parotid gland itself are relative to the **retromandibular vein** and **external carotid artery**, not the mastoid and styloid processes.

Question 1238: Tensor tympani is attached to?

A. Malleus (Correct Answer)
B. Incus
C. Stapes
D. Tympanic membrane

Explanation: ***Malleus*** - The **tensor tympani muscle** contracts to pull the malleus inward, **increasing tension** on the tympanic membrane [1]. - This action **dampens vibrations** transmitted to the inner ear, particularly protecting against loud sounds [1]. *Incus* - The incus is the **middle ossicle** in the sound conduction chain, connected to the malleus and stapes [1]. - It does not have a direct muscular attachment from the tensor tympani. *Stapes* - The stapes is the **innermost ossicle**, articulating with the oval window [1]. - The **stapedius muscle** attaches to the stapes, not the tensor tympani, and also dampens sound [1]. *Tympanic membrane* - While the tensor tympani's action **increases tension** on the **tympanic membrane** via the malleus, it does not directly attach to the membrane [1]. - The malleus is embedded within the tympanic membrane [1].

Question 1239: MacEwen's triangle is the landmark for:

A. Maxillary sinus
B. Frontal sinus
C. Mastoid antrum (Correct Answer)
D. None of the options

Explanation: ***Mastoid antrum*** - **MacEwen's triangle** (or suprameatal triangle) is an important anatomical landmark on the lateral surface of the mastoid process, indicating the approximate position of the **mastoid antrum**. - It is bounded anteriorly by the posterior free margin of the **bony external auditory canal**, superiorly by the supramastoid crest (temporal line), and posteriorly by a line tangential to the posterior external auditory canal. *Maxillary sinus* - The **maxillary sinus** (antrum of Highmore) is located within the body of the maxilla, inferior to the orbit and lateral to the nasal cavity. - Its location is not related to MacEwen's triangle, which is found on the temporal bone. *Frontal sinus* - The **frontal sinus** is located within the frontal bone, superior to the orbits and nasal cavity. - This sinus is not anatomically associated with MacEwen's triangle; the triangle is a landmark for the mastoid air cells. *None of the options* - This is incorrect because **MacEwen's triangle** is indeed a well-established landmark for the **mastoid antrum**. - Its clinical significance lies in providing a guide for surgical access to the mastoid antrum during mastoidectomy.

Question 1240: Trismus in parapharyngeal abscess is due to spasm of:

A. Medial pterygoid (Correct Answer)
B. Temporalis
C. Masseter muscle
D. Lateral pterygoid

Explanation: ***Medial pterygoid*** - The **medial pterygoid muscle** is intimately associated with the parapharyngeal space, and inflammation or infection (abscess) in this region directly irritates it. - **Spasm** of the medial pterygoid muscle, a primary muscle of mastication involved in jaw closure, is the direct cause of **trismus** (difficulty opening the mouth) in parapharyngeal abscess. *Masseter muscle* - While the **masseter** is a strong muscle of mastication and contributes to jaw closure, it is located more superficially and is less directly affected by an abscess in the parapharyngeal space. - Its involvement in trismus due to parapharyngeal abscess is typically secondary, arising from generalized muscle guarding rather than direct irritation. *Lateral pterygoid* - The **lateral pterygoid muscle** is primarily involved in jaw opening (depression) and protrusion. - Spasm of this muscle would typically lead to difficulty closing the jaw or deviations, rather than the profound difficulty in opening characteristic of trismus. *Temporalis* - The **temporalis muscle** is a major muscle for jaw elevation and retraction, contributing significantly to biting force. - While temporalis spasm can cause trismus, it is less directly impacted by a parapharyngeal abscess compared to the medial pterygoid muscle.

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