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: 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: The X-ray shows plating done for a fracture. How does this fracture heal?

Primary healing. **Primary healing** - **Plating of a fracture** aims to achieve **absolute stability** at the fracture site, which facilitates primary bone healing. - In primary healing, there is **direct bone formation** across the fracture gap without the formation of a significant callus. *Secondary healing* - Secondary healing involves the formation of a **callus** (fibrous tissue, cartilage, and immature bone) to bridge the fracture gap. - This type of healing occurs in situations with **relative stability** and some micromotion at the fracture site, such as with casting or intramedullary nailing. *Tertiary healing* - **Tertiary healing** is not a recognized term in the context of fracture healing. - Bone healing typically involves either primary or secondary mechanisms depending on the stability achieved. *Distraction histiogenesis* - **Distraction histiogenesis** is the process by which new bone is formed between bone surfaces that are gradually pulled apart using an external fixator (**distraction osteogenesis**). - This is used in procedures like **limb lengthening** and is distinct from the direct healing of a fracture fixed with a plate.

Q: Identify the condition shown in the image:

Spondylolysis. ***Spondylolysis*** * The image shows a **break in the pars interarticularis** of a vertebra, indicated by the arrow, which is characteristic of spondylolysis. * This condition is a **stress fracture** or defect in the pars interarticularis, a bony segment connecting the superior and inferior articular facets. *Renal osteodystrophy* * Renal osteodystrophy refers to a spectrum of **bone abnormalities** that occur in chronic kidney disease, not a specific vertebral fracture pattern. * It typically involves features such as **osteomalacia**, **osteitis fibrosa cystica**, or **osteoporosis**, which are not directly depicted as a fracture in this image. *Spondylolisthesis* * Spondylolisthesis is the **anterior slippage** of one vertebral body over another, which can be caused by bilateral spondylolysis but is not directly shown as a slip in this specific image. * The image distinctly highlights the **fracture line** itself, rather than the displacement of the vertebral body. *Tuberculosis (TB)* * Spinal tuberculosis (Pott's disease) typically presents with **destruction of vertebral bodies**, disc space narrowing, and often a **paravertebral abscess**. * The image does not show these features; instead, it demonstrates a clear **bony defect** in the pars interarticularis.

Q: A 10-year-old boy presents with the physical findings shown in the image, characterized by inward angulation of the elbows. What is the most likely diagnosis?

Cubitus varus deformity. ***Cubitus varus deformity*** - The image clearly illustrates an **inward angulation of the elbow** (gunstock deformity), which is characteristic of **cubitus varus**. This often occurs after a supracondylar fracture of the humerus that heals with malunion. - This deformity typically results in a decreased or reversed carrying angle of the elbow. *Madelung deformity* - This is a rare congenital anomaly characterized by **dorsal and radial bowing of the distal radius** and premature fusion of the ulnar physis. - It primarily affects the wrist, leading to a visible prominence of the distal ulna and carpal bone subluxation, which is not depicted in the elbow region in the image. *Nursemaid's elbow* - This is a common injury in young children where the **radial head is subluxated** from the annular ligament, often due to a sudden pull on the forearm. - It presents as acute pain and refusal to use the arm, but does not involve a chronic structural deformity or angulation of the elbow joint as shown in the image. *Klippel-Feil syndrome* - This is a rare congenital disorder characterized by the **fusion of two or more cervical vertebrae**. - Its primary manifestations are a short neck, low posterior hairline, and restricted neck movement, with no direct involvement or deformity of the elbow joint itself.

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: After ovulation, the oocyte is:

Secondary oocyte arrested in metaphase II. ***Secondary oocyte arrested in metaphase II*** - After ovulation, the **oocyte** has completed **meiosis I** and extruded the **first polar body**, becoming a secondary oocyte. - It then arrests in **metaphase II** and will only complete meiosis II upon fertilization by a sperm. *Primary oocyte arrested in prophase II* - A **primary oocyte** is the stage before meiosis I is completed, and it is arrested in **prophase I** at birth, not prophase II. - Oocytes do not arrest in **prophase II** during normal meiotic development. *Secondary oocyte arrested in prophase II* - While it is a **secondary oocyte** that is ovulated, it is arrested in **metaphase II**, not prophase II. - **Prophase II** is a transient stage that occurs just before metaphase II, and arrest at this stage is not typical for the ovulated oocyte. *Primary oocyte arrested in prophase I* - This describes the state of the oocyte from **fetal development** until just before ovulation. - A **primary oocyte** completes meiosis I only in response to the **LH surge** before ovulation.

Q: Which of the following prevents polyspermy?

Cortical reaction. ***Cortical reaction*** - The **cortical reaction** is the primary mechanism that prevents **polyspermy** following sperm-oocyte fusion. - Upon fusion, **cortical granules** in the oocyte cytoplasm release their contents (including proteases and peroxidases) into the **perivitelline space**. - These enzymes modify the **zona pellucida** proteins, making it impermeable to additional sperm - this modification is called the **zona reaction**. - The cortical reaction represents both the **fast block** (depolarization of oocyte membrane) and **slow block** (zona pellucida hardening) to polyspermy. *Zona reaction* - The **zona reaction** is the biochemical and structural change that occurs in the zona pellucida as a **result** of the cortical reaction. - It involves hardening and altered permeability of the zona pellucida, making it resistant to sperm penetration. - While this is the ultimate barrier to polyspermy, it is a **consequence** rather than the active mechanism - the cortical reaction is the causative event. *Acrosome reaction* - The **acrosome reaction** is essential for fertilization, allowing sperm to penetrate the zona pellucida by releasing hydrolytic enzymes. - It **facilitates** sperm entry rather than preventing additional sperm from binding. - This reaction must occur for the first sperm to fertilize the egg but plays no role in preventing polyspermy. *Capacitation* - **Capacitation** is the physiological maturation of sperm in the female reproductive tract. - It enables sperm to undergo the acrosome reaction and achieve fertilization competence. - It is a preparatory process and has no role in preventing polyspermy.

Question 1

The "O sign" formed by the thumb and index finger is affected. Which muscle is most likely injured?

Accepted Answer

Flexor pollicis longus

Answer

Opponens pollicis

Answer

Flexor pollicis brevis

Answer

Abductor pollicis brevis

Answer

Flexor digitorum profundus (index finger)

Question 2

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 3

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 4

The X-ray shows plating done for a fracture. How does this fracture heal?

Accepted Answer

Primary healing

Answer

Secondary healing

Answer

Tertiary healing

Answer

Distraction histiogenesis

Question 5

Identify the condition shown in the image:

Accepted Answer

Spondylolysis

Answer

Renal osteodystrophy

Answer

Spondylolisthesis

Answer

Tuberculosis (TB)

Question 6

A 10-year-old boy presents with the physical findings shown in the image, characterized by inward angulation of the elbows. What is the most likely diagnosis?

Accepted Answer

Cubitus varus deformity

Answer

Madelung deformity

Answer

Nursemaid's elbow

Answer

Klippel-Feil syndrome

Question 7

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

Accepted Answer

Epiphyseal plate

Answer

Diaphysis

Answer

Epiphysis

Answer

Metaphysis

Question 8

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 9

After ovulation, the oocyte is:

Accepted Answer

Secondary oocyte arrested in metaphase II

Answer

Primary oocyte arrested in prophase II

Answer

Secondary oocyte arrested in prophase II

Answer

Primary oocyte arrested in prophase I

Question 10

Which of the following prevents polyspermy?

Accepted Answer

Cortical reaction

Answer

Acrosome reaction

Answer

Zona reaction

Answer

Capacitation

NEET-PG 2024

Anatomy

Internal Medicine

Orthopaedics

Pediatrics

Physiology