NEET-PG 2013 - Anatomy Practice Questions

Q: T cells in lymph node are present in:

Paracortical area. ***Paracortical area*** - The **paracortical area** contains a high concentration of **T cells**, particularly activated T cells in response to antigenic stimulation [1]. - It plays a crucial role in **immune responses**, bridging the cortex and medulla of the lymph node [1]. *Mantle layer* - The **mantle layer** surrounds the follicles and primarily consists of **B cells**, not T cells. - It is involved in the initial immune response but does not contain a significant number of T lymphocytes. *Medullary cords* - **Medullary cords** mainly contain **plasma cells** and macrophages, with very few T cells present. - Their primary function is the secretion of antibodies rather than T cell activation or response. *Cortical follicles* - **Cortical follicles** are primarily sites for **B cell activation and proliferation**. - While they may have some T cells at their periphery, the majority of T cells are located in the paracortical area.

Q: What is the longest part of the optic nerve?

Intraorbital. ***Intraorbital*** - The **intraorbital segment** is the **longest portion** of the optic nerve, measuring approximately **25-30 mm**. - It extends from the posterior pole of the eyeball to the **optic canal** and is characterized by a curved, **S-shaped course** within the orbit. - This excess length (approximately 8 mm more than the distance it spans) allows for **free eye movements** without putting tension on the nerve. *Intracranial* - The **intracranial portion** extends from the **optic canal** to the **optic chiasm**, measuring approximately **10-16 mm**. - While often mistakenly thought to be the longest, it is actually the **second longest segment**. - This segment is crucial for the formation of the **optic chiasm** where partial decussation of fibers occurs. *Intracanalicular* - The **intracanalicular portion** passes through the **optic canal** within the sphenoid bone, measuring approximately **4-10 mm**. - This segment is relatively short and constricted, making it vulnerable to compression in conditions like optic nerve gliomas or meningiomas. *Intraocular* - The **intraocular portion** (optic disc) is the **shortest segment**, measuring only about **1 mm**. - It passes through the **lamina cribrosa** of the sclera and is visible on fundoscopy as the optic disc.

Q: The junction between Retina & Ciliary body is?

Ora serrata. ***Ora serrata*** - The **ora serrata** represents the **anterior-most jagged edge** of the retina where the sensory retina terminates. [1] - It marks the transition point where the neural retina becomes the **non-photoreceptive ciliary body epithelium**. *Equator* - The **equator** is the imaginary line circling the globe of the eye, approximately equidistant from the anterior and posterior poles. - It is a landmark on the retina itself, indicating the approximate middle of the retina, and not its junction with the ciliary body. *Pars plicata* - The **pars plicata** is the anterior, folded portion of the **ciliary body** that produces aqueous humor. - While part of the ciliary body, it is anterior to the junction with the retina and not the junction itself. *Pars plana* - The **pars plana** is the posterior, relatively flat portion of the **ciliary body**, located between the ora serrata and the pars plicata. - It is a part of the ciliary body immediately adjacent to the ora serrata, but the ora serrata itself is the definitive junction.

Q: Which of the following statements about articular cartilage is true?

Has no nerve supply. ***Has no nerve supply*** - Articular cartilage is **aneural**, meaning it lacks nerve endings, which is why damage to it doesn't immediately cause pain until underlying bone or surrounding tissues are affected [1]. - Its aneural nature contributes to its low metabolic activity and limited capacity for repair. *Very vascular structure* - Articular cartilage is **avascular**, meaning it lacks a direct blood supply [1]. - It receives nutrients primarily through diffusion from the synovial fluid [1]. *Surrounded by thick perichondrium* - Articular cartilage is typically **not covered by a perichondrium**, unlike most other types of cartilage. - The absence of perichondrium prevents potential ossification of the articular surface. *Fibrocartilage* - Articular cartilage is primarily composed of **hyaline cartilage**, not fibrocartilage [1]. - **Hyaline cartilage** provides a smooth, low-friction surface for joint movement and acts as a shock absorber [1].

Q: Upper Lid Retractors include

Levator palpebrae superioris & Muller muscle. ***Levator palpebrae superioris & Muller muscle*** - The **levator palpebrae superioris (LPS)** is the primary muscle responsible for lifting the upper eyelid. It is a striated muscle innervated by the oculomotor nerve (CN III). - **Müller's muscle** (also known as the superior tarsal muscle) is a smooth muscle that provides an additional, sustained lift to the upper eyelid. It is sympathetically innervated. *Muller muscle and superior rectus* - While **Müller's muscle** is an upper lid retractor, the **superior rectus** muscle primarily acts to elevate and adduct the eyeball, not the eyelid itself [1]. - The superior rectus muscle has only a minor, indirect role in upper eyelid elevation through its connection with the LPS aponeurosis. *Levator palpabrae superioris and superior oblique* - The **levator palpebrae superioris (LPS)** is a key upper lid retractor. - However, the **superior oblique** muscle is involved in depressing and intorting the eyeball [1], and has no direct role in upper eyelid retraction. *Superior oblique and superior rectus* - Neither the **superior oblique** nor the **superior rectus** muscles are primary upper lid retractors. - The superior oblique depresses and intorts the eye, while the superior rectus elevates and adducts the eye [1]. Both are extrinsic ocular muscles.

Q: During abdominal surgery under local anesthesia, the patient suddenly felt pain due to

Parietal peritoneum. ***Parietal peritoneum*** - The **parietal peritoneum** is richly innervated by somatic nerves (**spinal nerves**), making it highly sensitive to pain, pressure, and temperature. - When stimulated during surgery, even under local anesthesia which might not completely block deeper somatic nerves or if the local block is inadequate, it can cause the patient to suddenly feel **sharp, localized pain**. *Liver* - The liver itself has very few pain receptors in its parenchyma; pain from the liver typically arises from stretching of its fibrous capsule (**Glisson's capsule**). - This pain is usually dull and poorly localized, not the sudden, sharp pain typically experienced during surgical manipulation. *Intestines* - The intestines are primarily innervated by the **autonomic nervous system** and are sensitive to distension and ischemia, causing visceral pain, which is typically dull, crampy, and poorly localized. - They are generally not sensitive to cutting or burning, which are common surgical manipulations. *Visceral peritoneum* - The **visceral peritoneum** covers abdominal organs and is innervated by the autonomic nervous system, similar to the organs it covers. - Like the intestines, it is sensitive to stretch and ischemia, producing diffuse, poorly localized visceral pain rather than sharp, localized pain from surgical incision or manipulation.

Q: Which of the following conditions is least likely to cause bilateral recurrent laryngeal nerve palsy?

Aortic aneurysm. ***Aortic aneurysm*** - An aortic aneurysm, especially of the ascending aorta, is **less likely to cause bilateral recurrent laryngeal nerve palsy** because the left recurrent laryngeal nerve typically hooks under the aortic arch, while the right nerve hooks under the subclavian artery. - For **bilateral involvement**, two separate and simultaneous lesions affecting both nerves would be required at different anatomical locations with this etiology, making it a rare cause. *Thyroid carcinoma* - An aggressive **thyroid carcinoma** can directly invade or compress the recurrent laryngeal nerves (RLNs) due to their proximity to the thyroid gland. - If the carcinoma is extensive or multifocal, it can lead to **bilateral involvement** by affecting both nerves. *Lymphadenopathy* - Significant **cervical or mediastinal lymphadenopathy** (e.g., due to metastatic disease or lymphoma) can compress or encase both recurrent laryngeal nerves. - This proximity allows for potential **bilateral compression or damage** to the nerves as they ascend in the tracheoesophageal grooves. *Thyroid surgery* - **Thyroidectomy** is a common cause of recurrent laryngeal nerve injury due to the nerves' close anatomical relationship with the thyroid gland. - **Bilateral recurrent laryngeal nerve palsy** can occur if both nerves are damaged during dissection, often due to surgical misidentification, thermal injury, or traction.

Q: Which of the following arteries does NOT contribute to Little's area?

Posterior Ethmoidal artery. Posterior Ethmoidal artery - The posterior ethmoidal artery primarily supplies the posterior ethmoidal cells and part of the sphenoid sinus, but it does not contribute to the vascular plexus in Little's area. - Little's area, also known as Kiesselbach's plexus, is formed by anastomoses of several arteries on the anterior nasal septum. Sphenopalatine artery - The sphenopalatine artery, a terminal branch of the maxillary artery, is a major contributor to Little's area through its septal branch. - It supplies a significant portion of the nasal septum and is frequently involved in posterior epistaxis. Greater palatine artery - The greater palatine artery, a branch of the descending palatine artery (from the maxillary artery), enters the nasal cavity through the incisive canal and contributes to Little's area on the nasal septum. - It primarily supplies the hard palate and then anastomoses with other vessels in the anterior nasal septum. Anterior Ethmoidal artery - The anterior ethmoidal artery, a branch of the ophthalmic artery, is a key contributor to Little's area. - It supplies the anterior and middle ethmoidal cells and also contributes to the blood supply of the dura mater.

Q: A person is not able to extend his metacarpophalangeal joint. Injury to which of the following nerve result in this?

Posterior Interosseous nerve injury. Posterior Interosseous Nerve (PIN) injury - The Posterior Interosseous Nerve is the deep motor branch of the radial nerve that specifically innervates the extensor muscles of the fingers and thumb - These muscles include: Extensor Digitorum, Extensor Indicis, Extensor Digiti Minimi, Extensor Pollicis Longus and Brevis [1] - PIN injury causes inability to extend the MCP joints and interphalangeal joints of the fingers [1] - Wrist extension is preserved because the Extensor Carpi Radialis Longus (ECRL) and often ECRB are innervated by the radial nerve proper before it gives off the PIN [1] - This results in a characteristic finger drop without wrist drop Radial nerve injury - A high radial nerve injury (proximal, above the elbow) would cause both wrist drop AND finger extension loss - However, radial nerve injury at the spiral groove (most common site) typically spares the PIN or affects it less severely - The question asks specifically about isolated inability to extend MCP joints, which is the hallmark of PIN injury, not general radial nerve injury - Radial nerve proper gives branches to triceps, brachioradialis, and ECRL before dividing into PIN and superficial branch Ulnar nerve injury - The ulnar nerve innervates intrinsic hand muscles (interossei, lumbricals to digits 4-5, hypothenar muscles, adductor pollicis) [1] - Ulnar nerve injury causes claw hand deformity with MCP hyperextension (not loss of extension) and IP joint flexion - This is the opposite of what is described in the question Median nerve injury - The median nerve innervates the thenar muscles, lateral two lumbricals, and forearm flexors [1] - Median nerve injury causes ape hand deformity with loss of thumb opposition and flexion - It does not affect MCP joint extension, which is an extensor function

Question 1

In current medical practice, cephalic index is primarily used for

Accepted Answer

Assessment of craniosynostosis

Answer

Evaluation of skull deformities

Answer

Clinical documentation of head shape

Answer

Neurosurgical planning

Question 2

T cells in lymph node are present in:

Accepted Answer

Paracortical area

Answer

Mantle layer

Answer

Medullary cords

Answer

Cortical follicles

Question 3

What is the longest part of the optic nerve?

Accepted Answer

Intraorbital

Answer

Intracanalicular

Answer

Intraocular

Answer

Intracranial

Question 4

The junction between Retina & Ciliary body is?

Accepted Answer

Ora serrata

Answer

Equator

Answer

Pars plicata

Answer

Pars plana

Question 5

Which of the following statements about articular cartilage is true?

Accepted Answer

Has no nerve supply

Answer

Very vascular structure

Answer

Surrounded by thick perichondrium

Answer

Fibrocartilage

Question 6

Upper Lid Retractors include

Accepted Answer

Levator palpebrae superioris & Muller muscle

Answer

Muller muscle and superior rectus

Answer

Levator palpebrae superioris and superior oblique

Answer

Superior oblique and superior rectus

Question 7

During abdominal surgery under local anesthesia, the patient suddenly felt pain due to

Accepted Answer

Parietal peritoneum

Answer

Liver

Answer

Intestines

Answer

Visceral peritoneum

Question 8

Which of the following conditions is least likely to cause bilateral recurrent laryngeal nerve palsy?

Accepted Answer

Aortic aneurysm

Answer

Thyroid carcinoma

Answer

Lymphadenopathy

Answer

Thyroid surgery

Question 9

Which of the following arteries does NOT contribute to Little's area?

Accepted Answer

Posterior Ethmoidal artery

Answer

Sphenopalatine artery

Answer

Greater palatine artery

Answer

Anterior Ethmoidal artery

Question 10

A person is not able to extend his metacarpophalangeal joint. Injury to which of the following nerve result in this?

Accepted Answer

Posterior Interosseous nerve injury

Answer

Radial nerve injury

Answer

Ulnar nerve injury

Answer

Median nerve injury

NEET-PG 2013 — Anatomy