FMGE 2018 — Anatomy

Q: Retraction of scapula is done by

Trapezius. ***Trapezius*** - The **trapezius** muscle, particularly the middle fibers, is responsible for **retracting the scapula**, pulling it medially towards the vertebral column. - This action is crucial for stabilizing the shoulder girdle and enabling various arm movements. *Serratus anterior* - The **serratus anterior** is primarily responsible for **protraction of the scapula** (pulling it forward) and stabilizing it against the thoracic wall. - It also aids in upward rotation of the scapula. *Supraspinatus* - The **supraspinatus** muscle is a rotator cuff muscle involved in the **initiation of arm abduction** (lifting the arm away from the body). - It does not directly contribute to scapular retraction. *Subscapularis* - The **subscapularis** is another rotator cuff muscle, primarily responsible for **internal rotation of the arm** and stabilization of the glenohumeral joint. - It has no direct role in scapular retraction. [Practice more Anatomy PYQs on OnCourse]

Q: Eustachian tube develops from:

1st pharyngeal pouch. ***1st pharyngeal pouch*** - The **Eustachian tube** (also known as the pharyngotympanic tube or auditory tube) develops from the **endoderm** of the first pharyngeal pouch. - This embryonic structure also gives rise to the **tympanic cavity** and the mastoid air cells, forming part of the middle ear. *2nd and 3rd pharyngeal pouch* - The **second pharyngeal pouch** primarily contributes to the development of the **palatine tonsils**. - The **third pharyngeal pouch** is involved in the formation of the **inferior parathyroid glands** and the **thymus**. *3rd pharyngeal pouch* - The **third pharyngeal pouch** specifically differentiates into the **inferior parathyroid glands** and the **thymus**. - It does not contribute to the formation of the Eustachian tube. *2nd pharyngeal pouch* - The **second pharyngeal pouch** is primarily associated with the development of the **palatine tonsils** and the tonsillar fossa. - It does not play a role in the embryological development of the Eustachian tube. [Practice more Anatomy PYQs on OnCourse]

Q: CSF Otorrhea is due to trauma of:

Petrous temporal bone. ***Petrous temporal bone*** - **CSF otorrhea** (leakage of cerebrospinal fluid from the ear) most commonly results from a fracture of the **petrous portion of the temporal bone**. - This bone forms part of the skull base and houses structures of the inner and middle ear, a fracture here can create a direct communication between the **subarachnoid space** and the external ear canal. *Tympanic membrane* - A rupture of the **tympanic membrane** alone would lead to **otorrhea** (ear discharge), but it would primarily involve blood or middle ear fluid, not CSF. - While a ruptured tympanic membrane is necessary for CSF to exit the ear canal, the source of the CSF leak itself is proximal to the middle ear. *Cribriform plate* - A fracture of the **cribriform plate** typically results in **CSF rhinorrhea** (CSF leakage from the nose), as it is located structurally above the nasal cavity. - It is not directly involved in CSF leakage from the ear. *Parietal bone* - Fractures of the **parietal bone** are typically associated with epidural or subdural hematomas or brain injury, depending on the extent of the trauma. - They are not a usual cause of CSF leakage from the ear since this bone does not contain CSF pathways that directly communicate with the ear. [Practice more Anatomy PYQs on OnCourse]

Q: Sensory innervation of the cornea is by which nerve?

5th (ophthalmic division of the trigeminal nerve). ***5th (ophthalmic division of the trigeminal nerve)*** - The **trigeminal nerve (CN V)** is responsible for sensory innervation of the face, and its **ophthalmic division (V1)** specifically supplies the cornea. - This extensive sensory innervation explains the **extreme sensitivity of the cornea** to touch, temperature, and chemicals, and is crucial for the **corneal reflex**. *6th (Abducens nerve)* - The **abducens nerve (CN VI)** is a **motor nerve** responsible for innervating the **lateral rectus muscle**, which abducts the eye. - It has no role in the sensory innervation of the cornea. *3rd (Oculomotor nerve)* - The **oculomotor nerve (CN III)** is primarily a **motor nerve** responsible for innervating most of the **extraocular muscles** (superior, inferior, medial recti, inferior oblique) and the **levator palpebrae superioris**. - It also carries **parasympathetic fibers** for pupillary constriction and accommodation, but it does not provide sensory innervation to the cornea. *4th (Trochlear nerve)* - The **trochlear nerve (CN IV)** is a **motor nerve** that innervates the **superior oblique muscle**, which depresses and internally rotates the eye. - It has no function in corneal sensation. [Practice more Anatomy PYQs on OnCourse]

Q: Most medial nucleus of cerebellum is:

Fastigial. ***Fastigial*** - The **fastigial nucleus** is located most **medially** within the cerebellum, closest to the midline in the roof of the fourth ventricle [1]. - It is the most medial of the four deep cerebellar nuclei and is primarily associated with the **vestibulocerebellum** (flocculonodular lobe) [1]. - Functions: Maintains **balance, posture, and coordinated eye movements** via connections to vestibular nuclei and reticular formation [1]. *Dentate* - The **dentate nucleus** is the **largest and most lateral** of the cerebellar nuclei, with a characteristic crumpled sac-like appearance (resembling an olive). - Located deep within the **lateral cerebellar hemisphere** white matter [1]. - Associated with the **neocerebellum** (cerebrocerebellum) and involved in **planning and initiating voluntary movements** via the ventrolateral thalamus to motor cortex [1]. *Emboliform* - The **emboliform nucleus** is elongated and located **medial to the dentate** but **lateral to the globose** nucleus. - Together with the globose nucleus, forms the **interposed nuclei**. - Associated with the **spinocerebellum** and involved in **modulating limb movements** and adjusting ongoing motor activity [1]. *Globose* - The **globose nucleus** consists of rounded cell masses located **medial to emboliform** and **lateral to fastigial** nucleus. - Part of the **interposed nuclei** along with emboliform nucleus. - Functions in **fine-tuning and coordinating ongoing movements**, particularly of distal limbs. [Practice more Anatomy PYQs on OnCourse]

22 Previous Year Questions with Answers & Explanations

Questions

Retraction of scapula is done by

Eustachian tube develops from:

CSF Otorrhea is due to trauma of:

Sensory innervation of the cornea is by which nerve?

Most medial nucleus of cerebellum is:

Trismus is due to spasm of which of the following muscles

Adam's apple seen in boys is because of:

Winging of scapula is due to paralysis of

Foot eversion is caused by

Q10

Bleeding vessel in hemorrhoids is

FMGE 2018 - Anatomy FMGE Practice Questions and MCQs

Question 1: Retraction of scapula is done by

A. Serratus anterior
B. Supraspinatus
C. Trapezius (Correct Answer)
D. Subscapularis

Explanation: ***Trapezius*** - The **trapezius** muscle, particularly the middle fibers, is responsible for **retracting the scapula**, pulling it medially towards the vertebral column. - This action is crucial for stabilizing the shoulder girdle and enabling various arm movements. *Serratus anterior* - The **serratus anterior** is primarily responsible for **protraction of the scapula** (pulling it forward) and stabilizing it against the thoracic wall. - It also aids in upward rotation of the scapula. *Supraspinatus* - The **supraspinatus** muscle is a rotator cuff muscle involved in the **initiation of arm abduction** (lifting the arm away from the body). - It does not directly contribute to scapular retraction. *Subscapularis* - The **subscapularis** is another rotator cuff muscle, primarily responsible for **internal rotation of the arm** and stabilization of the glenohumeral joint. - It has no direct role in scapular retraction.

Question 2: Eustachian tube develops from:

A. 2nd and 3rd pharyngeal pouch
B. 3rd pharyngeal pouch
C. 2nd pharyngeal pouch
D. 1st pharyngeal pouch (Correct Answer)

Explanation: ***1st pharyngeal pouch*** - The **Eustachian tube** (also known as the pharyngotympanic tube or auditory tube) develops from the **endoderm** of the first pharyngeal pouch. - This embryonic structure also gives rise to the **tympanic cavity** and the mastoid air cells, forming part of the middle ear. *2nd and 3rd pharyngeal pouch* - The **second pharyngeal pouch** primarily contributes to the development of the **palatine tonsils**. - The **third pharyngeal pouch** is involved in the formation of the **inferior parathyroid glands** and the **thymus**. *3rd pharyngeal pouch* - The **third pharyngeal pouch** specifically differentiates into the **inferior parathyroid glands** and the **thymus**. - It does not contribute to the formation of the Eustachian tube. *2nd pharyngeal pouch* - The **second pharyngeal pouch** is primarily associated with the development of the **palatine tonsils** and the tonsillar fossa. - It does not play a role in the embryological development of the Eustachian tube.

Question 3: CSF Otorrhea is due to trauma of:

A. Tympanic membrane
B. Cribriform plate
C. Parietal bone
D. Petrous temporal bone (Correct Answer)

Explanation: ***Petrous temporal bone*** - **CSF otorrhea** (leakage of cerebrospinal fluid from the ear) most commonly results from a fracture of the **petrous portion of the temporal bone**. - This bone forms part of the skull base and houses structures of the inner and middle ear, a fracture here can create a direct communication between the **subarachnoid space** and the external ear canal. *Tympanic membrane* - A rupture of the **tympanic membrane** alone would lead to **otorrhea** (ear discharge), but it would primarily involve blood or middle ear fluid, not CSF. - While a ruptured tympanic membrane is necessary for CSF to exit the ear canal, the source of the CSF leak itself is proximal to the middle ear. *Cribriform plate* - A fracture of the **cribriform plate** typically results in **CSF rhinorrhea** (CSF leakage from the nose), as it is located structurally above the nasal cavity. - It is not directly involved in CSF leakage from the ear. *Parietal bone* - Fractures of the **parietal bone** are typically associated with epidural or subdural hematomas or brain injury, depending on the extent of the trauma. - They are not a usual cause of CSF leakage from the ear since this bone does not contain CSF pathways that directly communicate with the ear.

Question 4: Sensory innervation of the cornea is by which nerve?

A. 5th (ophthalmic division of the trigeminal nerve) (Correct Answer)
B. 6th (Abducens nerve)
C. 3rd (Oculomotor nerve)
D. 4th (Trochlear nerve)

Explanation: ***5th (ophthalmic division of the trigeminal nerve)*** - The **trigeminal nerve (CN V)** is responsible for sensory innervation of the face, and its **ophthalmic division (V1)** specifically supplies the cornea. - This extensive sensory innervation explains the **extreme sensitivity of the cornea** to touch, temperature, and chemicals, and is crucial for the **corneal reflex**. *6th (Abducens nerve)* - The **abducens nerve (CN VI)** is a **motor nerve** responsible for innervating the **lateral rectus muscle**, which abducts the eye. - It has no role in the sensory innervation of the cornea. *3rd (Oculomotor nerve)* - The **oculomotor nerve (CN III)** is primarily a **motor nerve** responsible for innervating most of the **extraocular muscles** (superior, inferior, medial recti, inferior oblique) and the **levator palpebrae superioris**. - It also carries **parasympathetic fibers** for pupillary constriction and accommodation, but it does not provide sensory innervation to the cornea. *4th (Trochlear nerve)* - The **trochlear nerve (CN IV)** is a **motor nerve** that innervates the **superior oblique muscle**, which depresses and internally rotates the eye. - It has no function in corneal sensation.

Question 5: Most medial nucleus of cerebellum is:

A. Dentate
B. Emboliform
C. Globose
D. Fastigial (Correct Answer)

Explanation: ***Fastigial*** - The **fastigial nucleus** is located most **medially** within the cerebellum, closest to the midline in the roof of the fourth ventricle [1]. - It is the most medial of the four deep cerebellar nuclei and is primarily associated with the **vestibulocerebellum** (flocculonodular lobe) [1]. - Functions: Maintains **balance, posture, and coordinated eye movements** via connections to vestibular nuclei and reticular formation [1]. *Dentate* - The **dentate nucleus** is the **largest and most lateral** of the cerebellar nuclei, with a characteristic crumpled sac-like appearance (resembling an olive). - Located deep within the **lateral cerebellar hemisphere** white matter [1]. - Associated with the **neocerebellum** (cerebrocerebellum) and involved in **planning and initiating voluntary movements** via the ventrolateral thalamus to motor cortex [1]. *Emboliform* - The **emboliform nucleus** is elongated and located **medial to the dentate** but **lateral to the globose** nucleus. - Together with the globose nucleus, forms the **interposed nuclei**. - Associated with the **spinocerebellum** and involved in **modulating limb movements** and adjusting ongoing motor activity [1]. *Globose* - The **globose nucleus** consists of rounded cell masses located **medial to emboliform** and **lateral to fastigial** nucleus. - Part of the **interposed nuclei** along with emboliform nucleus. - Functions in **fine-tuning and coordinating ongoing movements**, particularly of distal limbs.

Question 6: Trismus is due to spasm of which of the following muscles

A. Mentalis
B. Lateral pterygoid
C. Buccinator
D. Medial pterygoid (Correct Answer)

Explanation: ***Medial pterygoid*** - **Trismus** is characterized by persistent spasm of the **muscles of mastication**, leading to difficulty opening the mouth. - The **medial pterygoid** is a strong jaw **closer** muscle, and its spasm contributes significantly to trismus along with other masticatory muscles (masseter and temporalis). - Among the given options, medial pterygoid is the muscle of mastication that causes trismus when in spasm. *Mentalis* - The **mentalis muscle** is primarily involved in **pouting** and elevating the lower lip. - While it affects the lower face, it does not directly control jaw opening or closing to cause trismus. - It is **not a muscle of mastication**. *Lateral pterygoid* - The **lateral pterygoid muscle** is primarily responsible for **depressing** (opening) the jaw and is also involved in protrusion and side-to-side movements. - While it is a muscle of mastication, in the context of trismus (jaw closure spasm), the **medial pterygoid** (jaw closer) is more directly implicated than the lateral pterygoid. *Buccinator* - The **buccinator muscle** forms the muscular wall of the cheek and is involved in **chewing**, whistling, and keeping food between the teeth. - It does not directly control jaw opening or closing, and its spasm would not be the primary cause of trismus. - It is **not a muscle of mastication**.

Question 7: Adam's apple seen in boys is because of:

A. Thyroid cartilage (Correct Answer)
B. Tracheal rings
C. Hyoid bone
D. Cricoid cartilage

Explanation: Thyroid cartilage - The "Adam's apple" is a common term for the laryngeal prominence, which is formed by the anterior projection of the thyroid cartilage. - During puberty in males, the thyroid cartilage grows significantly, leading to a more prominent protrusion and deepening of the voice [1]. Tracheal rings - The tracheal rings are C-shaped cartilages that provide structural support to the trachea, preventing its collapse. - They are located inferior to the larynx and are not visible externally as a distinct prominence like the Adam's apple. Hyoid bone - The hyoid bone is a U-shaped bone located in the anterior neck between the chin and the thyroid cartilage. - It is unique because it is the only bone in the human body that does not articulate with any other bone; it serves as an anchor for muscles of the tongue and floor of the mouth. Cricoid cartilage - The cricoid cartilage is a ring-shaped cartilage located inferior to the thyroid cartilage, forming the base of the larynx. - While it is a part of the larynx, its anterior projection is not as prominent as that of the thyroid cartilage, and it does not form the "Adam's apple."

Question 8: Winging of scapula is due to paralysis of

A. Serratus anterior (Correct Answer)
B. Rhomboid major
C. Trapezius
D. Levator scapulae

Explanation: ***Serratus anterior*** - The **serratus anterior muscle** is responsible for **protraction and rotation of the scapula**, holding it close to the thoracic wall. - Paralysis of this muscle, often due to injury to the **long thoracic nerve**, causes the **medial border of the scapula** to protrude posteriorly, a condition known as **medial scapular winging**. - This is the **classic and most common cause** of scapular winging. *Rhomboid major* - The rhomboid major muscle primarily performs **retraction and downward rotation of the scapula**. - Paralysis of this muscle would lead to the scapula being displaced laterally and superiorly, not winging. *Trapezius* - The trapezius muscle has multiple actions, including **elevating, depressing, retracting, and rotating the scapula**. - Paralysis of the trapezius (e.g., due to **accessory nerve damage**) can cause **lateral scapular winging** where the inferior angle protrudes, along with shoulder drooping and difficulty shrugging. - However, **serratus anterior paralysis** is the classic answer for scapular winging in exam contexts. *Levator scapulae* - The levator scapulae muscle is primarily involved in **elevating and downwardly rotating the scapula**. - Dysfunction of this muscle would impair shoulder elevation but would not be the direct cause of scapular winging.

Question 9: Foot eversion is caused by

A. Tibialis anterior
B. Tibialis posterior
C. Peroneus longus (Correct Answer)
D. Extensor digitorum

Explanation: ***Peroneus longus*** - The **peroneus longus** muscle (fibularis longus) is a primary evertor of the foot. - It originates from the head and upper lateral surface of the fibula, inserts into the medial cuneiform and first metatarsal, and its contraction pulls the foot outwards and downwards. *Tibialis anterior* - The **tibialis anterior** is the primary dorsiflexor and invertor of the foot. - It pulls the foot upwards and inwards, which is the opposite action of eversion. *Tibialis posterior* - The **tibialis posterior** is a strong invertor and plantar flexor of the foot. - It contributes to maintaining the arch of the foot and does not cause eversion. *Extensor digitorum* - The **extensor digitorum longus** primarily extends the toes and assists in dorsiflexion of the ankle. - While it may have a slight eversion component, it is not the primary muscle responsible for foot eversion.

Question 10: Bleeding vessel in hemorrhoids is

A. Superior rectal vein
B. Middle rectal vein
C. Middle rectal artery
D. Superior rectal artery (Correct Answer)

Explanation: Superior rectal artery - Hemorrhoidal bleeding primarily originates from the **terminal branches of the superior rectal artery** within the hemorrhoidal plexus. - The hemorrhoidal cushions contain **arteriovenous anastomoses**, and bleeding occurs from rupture or erosion of the **arterial component**. - This explains why hemorrhoidal bleeding is typically **bright red** (oxygenated arterial blood) and can be brisk. - Modern surgical treatments like **hemorrhoidal artery ligation (HAL)** specifically target these arterial branches, confirming the arterial source of bleeding. Superior rectal vein - While the superior rectal vein drains the hemorrhoidal plexus and is dilated in hemorrhoids, it is **not the primary source of bleeding**. - The venous component contributes to the cushion engorgement but the **actual bleeding is arterial** in nature. - This is an older, outdated concept that has been revised with modern understanding of hemorrhoidal pathophysiology. Middle rectal vein - The middle rectal vein drains the **muscular wall of the rectum** and has minimal involvement in the hemorrhoidal venous plexus. - It is not a significant contributor to hemorrhoidal bleeding. Middle rectal artery - The middle rectal artery provides collateral blood supply to the rectum but plays a **minor role** compared to the superior rectal artery. - The **superior rectal artery** is the dominant arterial supply to the internal hemorrhoidal plexus and is the primary bleeding source.