NEET-PG 2024 Practice Questions

Q: Ptosis in Horner syndrome is due to paralysis of which muscle?

Superior tarsal muscle. ***Superior tarsal muscle*** * The **superior tarsal muscle** (Müller's muscle) is a sympathetically innervated smooth muscle. * Its paralysis due to sympathetic denervation in **Horner syndrome** causes partial ptosis. *Orbitalis* * The **orbitalis muscle** (Müller's muscle) is a smooth muscle that spans the inferior orbital fissure and may help in protrusion of the eyeball; it is not directly responsible for eyelid elevation. * While also sympathetically innervated, its paralysis does not directly cause ptosis but may contribute to other subtle signs or symptoms. *Orbicularis oculi* * The **orbicularis oculi muscle** is responsible for eyelid closure, not elevation. * It is innervated by the **facial nerve (CN VII)**, and its dysfunction would lead to difficulty closing the eye, not ptosis. *Sphincter pupillae* * The **sphincter pupillae muscle** constricts the pupil and is innervated by the **parasympathetic system**. * In Horner syndrome, the dilator pupillae (sympathetically innervated) is affected, leading to miosis (small pupil), not ptosis, and the sphincter pupillae function is preserved.

Q: Identify the arrow marked nerve ![img-2.jpeg](img-2.jpeg)

Medial pectoral nerve. ***Medial pectoral nerve*** - The arrow points to a nerve that is seen perforating the **pectoralis minor muscle**. This is a key anatomical landmark for the **medial pectoral nerve**. - This nerve supplies both the **pectoralis major** and **pectoralis minor** muscles, originating from the medial cord of the brachial plexus. *Long thoracic nerve* - The **long thoracic nerve** typically runs superficial to the serratus anterior muscle, not perforating the pectoralis minor. - Injury to this nerve results in **winged scapula** due to paralysis of the serratus anterior, which is distinct from the function of the nerve shown. *Thoracodorsal nerve* - The **thoracodorsal nerve** primarily innervates the **latissimus dorsi muscle** and typically runs along the lateral border of the scapula and axilla, not in the anterior chest wall where the pectoralis minor is located. - It arises from the **posterior cord of the brachial plexus**. *Lateral pectoral nerve* - The **lateral pectoral nerve** arises from the lateral cord and typically supplies only the **pectoralis major muscle**. - It often passes **medial to the pectoralis minor muscle** or penetrates the muscle from a more lateral aspect, but does not perforate it in the characteristic way shown for the medial pectoral nerve. *Suprascapular nerve* - The **suprascapular nerve** arises from the **upper trunk of the brachial plexus** and passes through the **suprascapular notch** beneath the superior transverse scapular ligament. - It innervates the **supraspinatus** and **infraspinatus** muscles and is located in the posterior shoulder region, not in the anterior chest wall where the structure shown is located.

Q: The nerve passing through the arrow-marked region in the provided image has been lesioned. Which of the following is the most likely clinical presentation?

Loss of sensation in the maxillary area of the face. ***Loss of sensation in the maxillary area of the face*** - The arrow points to the **foramen rotundum**, which transmits the **maxillary nerve (V2)**, a branch of the trigeminal nerve. - Lesion of the maxillary nerve (V2) leads to sensory loss in the **maxillary region of the face**, including the cheek, upper lip, upper teeth, and palate. *Loss of sensation in the jaw area* - Sensation in the jaw area, including the lower teeth and chin, is primarily supplied by the **mandibular nerve (V3)**, which exits through the foramen ovale. - A lesion at the foramen rotundum would not directly affect V3. *Loss of sensation on the scalp and nose* - Sensation to the scalp (anterior part) and nose is primarily supplied by the **ophthalmic nerve (V1)**, which exits the skull through the superior orbital fissure. - The foramen rotundum is not involved in the passage of the ophthalmic nerve. *Loss of sensation in the mucosa of nasopharynx* - While parts of the nasopharynx mucosa receive innervation from V2, this is a very specific and limited area, and the primary and most prominent sensory loss from a V2 lesion would be in the **maxillary facial region**. - Other nerves like the glossopharyngeal nerve also contribute to nasopharyngeal sensation. *Loss of motor function to muscles of facial expression* - Motor function to muscles of facial expression is supplied by the **facial nerve (CN VII)**, not the maxillary nerve (V2). - The maxillary nerve is a purely **sensory** branch of the trigeminal nerve and has no motor function. - The facial nerve exits the skull through the stylomastoid foramen, not the foramen rotundum.

Q: A singer presents with difficulty singing at a high pitch. On examination, bowing of the vocal cord is observed on the right side. Which of the following muscles has likely been compromised?

Cricothyroid. ***Cricothyroid*** - The **cricothyroid muscle** is primarily responsible for **tensioning and elongating the vocal cords**, which is crucial for increasing vocal pitch. - Damage to this muscle or its innervation (superior laryngeal nerve) results in an inability to reach higher pitches and can cause **vocal cord bowing** due to reduced tension. *Posterior cricoarytenoid* - This muscle is the **primary abductor** of the vocal cords, meaning it opens the vocal cords for breathing. - Compromise would lead to difficulty breathing or a paralyzed vocal cord in the adducted position, not bowing with difficulty singing high notes. *Lateral cricoarytenoid* - The **lateral cricoarytenoid muscle** is a **vocal cord adductor** and rotator, bringing the vocal cords together to regulate voice intensity. - Dysfunction typically results in a weak and breathy voice, or difficulty bringing the cords together, not specifically difficulty with high pitch. *Thyroarytenoid* - The **thyroarytenoid muscle** (which includes the vocalis muscle) acts to **relax and shorten the vocal cords**, lowering pitch and modulating vocal cord tension. - Dysfunction would primarily lead to difficulty with lower pitches or a hoarse voice, as it prevents proper relaxation of the vocal cords.

Q: An alcoholic patient presents with a wide-based gait and nystagmus after a road traffic accident (RTA). Which lobe of the cerebellum is most likely affected?

Flocculonodular. ***Flocculonodular Lobe*** - The **flocculonodular lobe** (or vestibulocerebellum) is responsible for **balance and oculomotor control**. Its damage leads to **truncal ataxia** (wide-based gait) and **nystagmus**. [1] - This lobe is particularly vulnerable in **alcoholic patients**, as chronic alcohol exposure can cause atrophy and dysfunction. [3] *Dentate Nucleus* - The **dentate nucleus** is a deep cerebellar nucleus primarily involved in the **planning and initiation of voluntary movements**, not directly with balance or nystagmus. - Damage typically results in **intention tremor**, **dysmetria**, and **dysdiadochokinesia**, which are not the primary symptoms described. [2] *Anterior Lobe* - The **anterior lobe** (spinocerebellum) largely controls **limb coordination**. - Lesions here typically cause **ataxia of the limbs** (e.g., dysmetria, intention tremor), but are less directly associated with truncal ataxia or nystagmus as initial prominent signs compared to flocculonodular lobe damage. *Vermis* - The **vermis** is part of the spinocerebellum and plays a critical role in **truncal coordination**. - While damage here can cause **truncal ataxia**, the combination with **nystagmus** points more specifically to the flocculonodular lobe (vestibulocerebellum), which has strong connections to vestibular nuclei. [1], [3]

Q: Fracture at which site affects the longitudinal growth of a bone?

Epiphyseal plate. ***Epiphyseal plate*** - The **epiphyseal plate**, also known as the **growth plate**, is a cartilaginous disc responsible for the **longitudinal growth** of long bones. - A fracture in this region can damage the **chondrocytes** and disrupt the normal ossification process, potentially leading to **growth arrest** or limb length discrepancies. *Diaphysis* - The **diaphysis** is the **shaft** or central part of a long bone. - While a fracture here can cause pain and instability, it typically does not directly affect the **longitudinal growth** potential of the bone. *Epiphysis* - The **epiphysis** is the end part of a long bone, initially separated from the main bone by cartilage but later fused with it. - Although it contains the epiphyseal plate in growing individuals, a fracture to the epiphysis itself (excluding the growth plate) primarily affects the **joint surface** and stability, rather than longitudinal growth directly. *Metaphysis* - The **metaphysis** is the transitional zone between the diaphysis and the epiphysis, adjacent to the growth plate. - While fractures in this area can be close to the growth plate, a metaphyseal fracture generally does not directly damage the **growth plate cartilage** to the same extent as a fracture through the plate itself, making its impact on longitudinal growth less direct or severe.

Q: A neonate presents with failure to pass meconium. The structure absent in the pathology lies in which of the following layers?

C, D. ***C, D*** - The neonate's symptom of **failure to pass meconium** is characteristic of **Hirschsprung disease**, which is caused by the absence of **ganglion cells** in the distal colon. - The missing ganglion cells are typically found in the **submucosal (Meissner) plexus** and the **myenteric (Auerbach) plexus**, corresponding to layers C and D in the provided image. *A, B* - Layer A represents the **mucosa** (specifically the glandular epithelium), and layer B represents the **lamina propria** or potentially the muscularis mucosa. - These layers do not primarily house the ganglion cells implicated in Hirschsprung disease. *B, C* - Layer B is the **lamina propria** or **muscularis mucosa**, and layer C is the **submucosa**. - While the submucosa (C) contains the Meissner plexus, layer B does not contain ganglion cells relevant to this pathology. *B, D* - Layer B is the **lamina propria/muscularis mucosa**, and layer D is the **muscularis propria**. - While the myenteric plexus (associated with D) is affected in Hirschsprung disease, layer B does not contain ganglion cells, and this option incorrectly excludes the submucosal plexus (layer C), which also contains ganglion cells that are absent in this condition. *A, D* - Layer A is the **mucosa**, and layer D is the **muscularis propria** (outer muscle layer). - The mucosa (A) does not contain the ganglion cells, while the myenteric plexus (associated with D) is affected, but this option incorrectly includes A and omits the submucosal plexus (C).

Q: Match the following receptors with their correct functions: Receptors: 1. Ruffini corpuscle 2. Merkel cells 3. Pacinian corpuscle 4. Meissner's corpuscle Functions: A. Vibration B. Sustained pressure C. Stretching D. Fine touch Select the option that correctly matches each receptor (1-4) with its function (A-D).

1C 2B 3A 4D. ***1C 2B 3A 4D*** - **Ruffini corpuscles** (1) detect **stretching** (C) of the skin. They are **slow-adapting Type II mechanoreceptors** located deep in the dermis, responding to sustained skin stretch and contributing to proprioception. - **Merkel cells** (2) detect **sustained pressure** (B) and fine texture discrimination. They are **slow-adapting Type I mechanoreceptors** with the highest spatial resolution, providing detailed information about touch. - **Pacinian corpuscles** (3) detect **vibration** (A), particularly high-frequency vibrations (200-300 Hz). They are **rapidly adapting receptors** with an onion-like lamellated structure located deep in the dermis and subcutaneous tissue. - **Meissner's corpuscles** (4) detect **fine touch** (D) and light pressure. They are **rapidly adapting receptors** located in dermal papillae of glabrous (hairless) skin, particularly abundant in fingertips and lips. *1C 2D 3B 4A* - Incorrectly assigns Merkel cells to fine touch (should be sustained pressure) and Pacinian corpuscles to sustained pressure (should be vibration). - Meissner's corpuscles are mismatched with vibration instead of fine touch. *1D 2C 3B 4A* - Incorrectly assigns Ruffini corpuscles to fine touch (should be stretching) and Merkel cells to stretching (should be sustained pressure). - Pacinian corpuscles are mismatched with sustained pressure (should be vibration). - Meissner's corpuscles are mismatched with vibration (should be fine touch). *1B 2A 3D 4C* - Completely incorrect matching: Ruffini to sustained pressure, Merkel to vibration, Pacinian to fine touch, and Meissner's to stretching. - Demonstrates fundamental misunderstanding of mechanoreceptor functions.

Question 1

Ptosis in Horner syndrome is due to paralysis of which muscle?

Accepted Answer

Superior tarsal muscle

Answer

Orbitalis

Answer

Orbicularis oculi

Answer

Sphincter pupillae

Question 2

An absent gag reflex can result from injury to which of the following nerves?

Accepted Answer

Cranial Nerve IX (Glossopharyngeal) and Cranial Nerve X (Vagus)

Answer

Cranial Nerve VII (Facial) and Cranial Nerve V (Trigeminal)

Answer

Cranial Nerve V (Trigeminal) and Cranial Nerve IX (Glossopharyngeal)

Answer

Cranial Nerve X (Vagus) and Cranial Nerve VII (Facial)

Answer

Cranial Nerve XII (Hypoglossal) and Cranial Nerve X (Vagus)

Question 3

Identify the arrow marked nerve
![img-2.jpeg](img-2.jpeg)

Accepted Answer

Medial pectoral nerve

Answer

Long thoracic nerve

Answer

Thoracodorsal nerve

Answer

Lateral pectoral nerve

Answer

Suprascapular nerve

Question 4

Identify the labeling correctly
![img-3.jpeg](img-3.jpeg)

Accepted Answer

A - Ascending aorta, B - Pulmonary trunk, C - Superior vena cava, D - Descending aorta

Answer

A - Ascending aorta, B - Superior vena cava, C - Pulmonary trunk, D - Descending aorta

Answer

A - Superior vena cava, B - Pulmonary trunk, C - Ascending aorta, D - Descending aorta

Answer

A - Pulmonary trunk, B - Ascending aorta, C - Superior vena cava, D - Descending aorta

Answer

A - Ascending aorta, B - Pulmonary trunk, C - Descending aorta, D - Superior vena cava

Question 5

The nerve passing through the arrow-marked region in the provided image has been lesioned. Which of the following is the most likely clinical presentation?

Accepted Answer

Loss of sensation in the maxillary area of the face

Answer

Loss of sensation in the jaw area

Answer

Loss of sensation on the scalp and nose

Answer

Loss of sensation in the mucosa of nasopharynx

Answer

Loss of motor function to muscles of facial expression

Question 6

A singer presents with difficulty singing at a high pitch. On examination, bowing of the vocal cord is observed on the right side. Which of the following muscles has likely been compromised?

Accepted Answer

Cricothyroid

Answer

Posterior cricoarytenoid

Answer

Lateral cricoarytenoid

Answer

Thyroarytenoid

Question 7

An alcoholic patient presents with a wide-based gait and nystagmus after a road traffic accident (RTA). Which lobe of the cerebellum is most likely affected?

Accepted Answer

Flocculonodular

Answer

Dentate

Answer

Anterior lobe

Answer

Vermis

Question 8

Fracture at which site affects the longitudinal growth of a bone?

Accepted Answer

Epiphyseal plate

Answer

Diaphysis

Answer

Epiphysis

Answer

Metaphysis

Question 9

A neonate presents with failure to pass meconium. The structure absent in the pathology lies in which of the following layers?

Accepted Answer

C, D

Answer

A, B

Answer

B, C

Answer

A, D

Answer

B, D

Question 10

Match the following receptors with their correct functions:

Receptors:
1. Ruffini corpuscle
2. Merkel cells
3. Pacinian corpuscle
4. Meissner's corpuscle

Functions:
A. Vibration
B. Sustained pressure
C. Stretching
D. Fine touch

Select the option that correctly matches each receptor (1-4) with its function (A-D).

Accepted Answer

1C 2B 3A 4D

Answer

1C 2D 3B 4A

Answer

1D 2C 3B 4A

Answer

1B 2A 3D 4C

NEET-PG 2024

Anatomy

ENT

Internal Medicine

Orthopaedics

Pediatrics

Physiology