NEET-PG 2012 Practice Questions

Q: Which structure(s) passes behind the inguinal ligament:

All of the options. ***Correct: All of the options*** All three structures pass deep to (behind) the inguinal ligament as they transition from the pelvis/abdomen into the thigh [1]. The inguinal ligament forms the superior border of the femoral triangle [1]. ***Femoral branch of genitofemoral nerve (Correct)*** - Pierces the **psoas major** muscle and descends along its anterior surface - Passes through the **lacuna musculorum** (lateral compartment) deep to the inguinal ligament - Lies **lateral to the femoral artery** - Provides sensory innervation to the skin over the femoral triangle ***Femoral vein (Correct)*** - Continuation of the popliteal vein from the lower limb - Passes through the **lacuna vasorum** (medial compartment/femoral canal) within the **femoral sheath** - Located **medial to the femoral artery** behind the inguinal ligament [1] - Carries deoxygenated blood back to the heart via the external iliac vein ***Psoas major (Correct)*** - Major hip flexor muscle originating from lumbar vertebrae (T12-L5) - Passes through the **lacuna musculorum** deep to the inguinal ligament - Located **lateral to the femoral vessels** - Combines with iliacus to form iliopsoas, inserting on the lesser trochanter of femur

Q: In walking, gravity tends to tilt pelvis and trunk to the unsupported side, the major factor in preventing this unwanted movement is?

Gluteus medius and minimus. ***Gluteus medius and minimus*** - The **gluteus medius** and **gluteus minimus** are essential **abductors** of the hip, primarily responsible for stabilizing the pelvis during the **single-limb support phase of gait**. - When one leg is lifted during walking, these muscles on the **stance leg side** contract to prevent the pelvis from tilting downwards on the unsupported swing leg side. *Adductor muscles* - **Adductor muscles** (adductor longus, brevis, magnus, pectineus, gracilis) primarily function to bring the thigh toward the midline of the body. - While they play a role in gait stability, their main action is not to prevent the lateral pelvic tilt described. *Quadriceps* - The quadriceps femoris group (rectus femoris, vastus lateralis, medialis, intermedius) are powerful **extensors of the knee**. - They are crucial for weight acceptance and propulsion during walking but do not directly prevent lateral pelvic tilt [1]. *Gluteus maximus* - The **gluteus maximus** is the largest and most powerful muscle of the hip, primarily responsible for **hip extension** and **external rotation**. - It is crucial for activities like climbing stairs or running, but its main role in normal walking is not to prevent lateral pelvic tilt; that function is more specific to the gluteus medius and minimus.

Q: What anatomical structures are involved in the closure of the fossa ovalis?

Septum primum + Septum secundum. The septum primum acts as a valve, closing against the septum secundum postnatally due to changes in atrial pressure. This fusion effectively closes the foramen ovale, leading to the formation of the fossa ovalis. The endocardial cushions are important for the formation of the atrial and ventricular septa, as well as the AV valves, but not directly for the closure of the fossa ovalis. The septum primum is directly involved, but its apposition with the endocardial cushions doesn't close the foramen ovale. While both structures contribute to heart development, their direct interaction is not responsible for the closure of the fossa ovalis. The septum secundum forms the muscular rim of the fossa ovalis, and the endocardial cushions are critical for atrial septation, but not the final closure here. This option is incorrect because the specific combination of septum primum and septum secundum is indeed responsible for the closure of the fossa ovalis.

Q: Which of the following is a traction epiphysis ?

Coracoid process of scapula. ***Coracoid process of scapula*** - A **traction epiphysis** (also called atavistic epiphysis) serves as an attachment site for muscles and tendons, transferring muscle force to the bone without bearing significant weight or forming articular surfaces. - The **coracoid process** is a classic example, anchoring the **pectoralis minor, coracobrachialis, and short head of biceps brachii**, as well as important ligaments (coracoclavicular and coracoacromial). - It develops from a separate ossification center purely for muscle and ligament attachment, not for articulation or weight-bearing. *Tibial condyles* - The **tibial condyles** are **pressure epiphyses** (articular epiphyses) that form the superior articular surface of the tibia. - They articulate with the femoral condyles to form the knee joint and bear significant weight during standing and movement. - Their primary function is joint formation and contribution to longitudinal bone growth. *Trochanter of femur* - The **greater and lesser trochanters** are large bony prominences that serve as muscle attachment sites, but they are better classified as **apophyses** rather than true traction epiphyses. - An **apophysis** is a secondary ossification center that does not contribute to longitudinal bone growth and serves primarily for muscle attachment. - While functionally similar to traction epiphyses, the term "traction epiphysis" is more specifically applied to structures like the coracoid process, tibial tuberosity, and calcaneal tuberosity. *Head of femur* - The **head of femur** is a classic **pressure epiphysis** that articulates with the acetabulum to form the hip joint. - It bears significant body weight and contributes to the longitudinal growth of the femur. - Its primary functions are joint formation and weight transmission, not muscle attachment.

Q: Coronary sinus develops from?

Sinus venosus. Sinus venosus - The sinus venosus is a primordial cardiac chamber that receives venous blood from the body and placenta in the early embryonic heart. - The left horn of the sinus venosus loses its connection with the systemic venous circulation and becomes the coronary sinus, which drains most of the cardiac veins into the right atrium [1, 4]. Truncus arteriosus - The truncus arteriosus is the embryonic precursor to the ascending aorta and pulmonary trunk. - It does not contribute to the development of the coronary sinus. Conus - The conus (or conus cordis) is the outflow portion of the primitive ventricle and differentiates into the outflow tracts of the right (infundibulum) and left (aortic vestibule) ventricles. - It is not involved in the formation of the coronary sinus. AV canal - The atrioventricular (AV) canal connects the primitive atrium and ventricle and is crucial for the formation of the AV valves and septation of the heart chambers. - It does not directly develop into the coronary sinus.

Q: Which is derived from Wolffian duct?

Appendix of epididymis. The **appendix of the epididymis** is a vestigial structure directly derived from the mesonephric (Wolffian) duct in males. It is an embryological remnant of this duct, located at the head of the epididymis. *Appendix of the testis* - The **appendix of the testis** (hydatid of Morgagni) is a remnant of the paramesonephric (Müllerian) duct, not the Wolffian duct. - It is usually found on the upper pole of the testis, typically near the epididymis. *Uterine structure* - **Uterine structures** (uterus, fallopian tubes, and upper vagina) are derived from the paramesonephric (Müllerian) ducts in females [1]. - The Wolffian ducts largely regress in females due to the absence of testosterone. *Hydatid of Morgagni* - The term **hydatid of Morgagni** can refer to the appendix of the testis (Müllerian duct remnant) or, less commonly, to the appendix of the epididymis (Wolffian duct remnant). - However, in common clinical and anatomical usage, it almost exclusively refers to the **appendix of the testis**, which is a Müllerian duct derivative.

Q: What is the classification of the Y chromosome?

Submetacentric. ***Submetacentric*** - The **Y chromosome** is classified as submetacentric because its **centromere** is located off-center, resulting in two arms of unequal length. - The short arm (Yp) is smaller than the long arm (Yq), but not as disproportionate as in acrocentric chromosomes. - The **X chromosome** is also submetacentric, making both sex chromosomes belong to this category. *Metacentric* - A **metacentric chromosome** has its **centromere** located in the middle, resulting in two arms of approximately equal length. - Examples include chromosomes 1, 3, 16, 19, and 20, which have nearly equal arm ratios unlike the Y chromosome. *Acrocentric* - An **acrocentric chromosome** has its **centromere** located very close to one end, creating one very short arm and one very long arm. - The five acrocentric human chromosomes are **13, 14, 15, 21, and 22**, which possess satellite DNA and nucleolar organizing regions (NORs) on their short arms. - The **Y chromosome is NOT acrocentric** despite historical confusion; it has a more centrally positioned centromere than true acrocentric chromosomes. *None of the options* - This option is incorrect because the Y chromosome has a specific and well-established classification as **submetacentric** based on its centromere position and arm ratio.

Q: Which of the following conditions can cause locking of the knee joint?

Loose body in knee joint. ***Loose body in knee joint*** - A **loose body** (e.g., a fragment of cartilage or bone) can get trapped between the articular surfaces of the knee joint, mechanically obstructing its movement and causing sudden, painful **locking**. - This mechanical impingement prevents full extension or flexion of the knee until the loose body shifts, leading to episodic locking symptoms. *Osgood Schlatter* - This condition involves inflammation and potential avulsion of the **tibial tuberosity** where the patellar tendon inserts. - It primarily causes pain and swelling below the kneecap, especially during physical activity, but does not typically result in true mechanical locking of the joint. *Tuberculosis of knee* - **Tuberculosis of the knee joint** is an infectious arthritis that causes chronic pain, swelling, and gradual destruction of articular cartilage and bone. - While it can lead to pain and limited range of motion, it usually does not present with the sudden, intermittent mechanical locking characteristic of a loose body. *a and b both* - Neither **Osgood Schlatter** nor **Tuberculosis of the knee** typically cause the characteristic mechanical locking sensation described for a loose body in the joint. - Each of these conditions has distinct pathophysiological mechanisms and clinical presentations that do not involve a physical obstruction causing locking.

Q: Haploid number of chromosomes is first seen in?

Secondary spermatocyte. ***Secondary spermatocyte*** - A secondary spermatocyte is formed after **meiosis I**, where the homologous chromosomes are separated, resulting in a cell with a **haploid number of chromosomes (n)**, although each chromosome still consists of two sister chromatids. - This is the **first stage** where haploidy is achieved in spermatogenesis. - These cells are transient and quickly undergo meiosis II to form spermatids. *Spermatogonia* - Spermatogonia are **diploid (2n)** germline stem cells that undergo mitosis to produce more spermatogonia or differentiate into primary spermatocytes. - They contain the full complement of chromosomes found in somatic cells. *Primary spermatocytes* - Primary spermatocytes are also **diploid (2n)** cells that enter meiosis I. - Before meiosis I, DNA replication occurs, so each chromosome consists of two sister chromatids, but the cell still maintains a diploid chromosome number. *Spermatids* - Spermatids are formed after **meiosis II** from secondary spermatocytes and are also **haploid (n)**. - However, secondary spermatocytes become haploid **earlier** in the process, immediately following the reductional division of meiosis I.

Question 1

Which of the following statements provides the MOST COMPLETE description of sclerotome function during vertebral development?

Accepted Answer

The sclerotome surrounds the notochord and the neural tube during development.

Answer

The notochord forms the nucleus pulposus.

Answer

The sclerotome contributes to the formation of vertebral bodies.

Answer

The sclerotome surrounds the notochord.

Question 2

Which structure(s) passes behind the inguinal ligament:

Accepted Answer

All of the options

Answer

Femoral branch of genitofemoral nerve

Answer

Femoral vein

Answer

Psoas major

Question 3

In walking, gravity tends to tilt pelvis and trunk to the unsupported side, the major factor in preventing this unwanted movement is?

Accepted Answer

Gluteus medius and minimus

Answer

Adductor muscles

Answer

Quadriceps

Answer

Gluteus maximus

Question 4

What anatomical structures are involved in the closure of the fossa ovalis?

Accepted Answer

Septum primum + Septum secundum

Answer

Septum primum + Endocardial cushion

Answer

Endocardial cushions + Septum secundum

Answer

None of the options

Question 5

Which of the following is a traction epiphysis ?

Accepted Answer

Coracoid process of scapula

Answer

Tibial condyles

Answer

Head of femur

Answer

Trochanter of femur

Question 6

Coronary sinus develops from?

Accepted Answer

Sinus venosus

Answer

Truncus arteriosus

Answer

Conus

Answer

AV canal

Question 7

Which is derived from Wolffian duct?

Accepted Answer

Appendix of epididymis

Answer

Appendix of the testis

Answer

Uterine structure

Answer

Hydatid of Morgagni

Question 8

What is the classification of the Y chromosome?

Accepted Answer

Submetacentric

Answer

Metacentric

Answer

Acrocentric

Answer

None of the options

Question 9

Which of the following conditions can cause locking of the knee joint?

Accepted Answer

Loose body in knee joint

Answer

Osgood Schlatter

Answer

Tuberculosis of knee

Answer

a and b both

Question 10

Haploid number of chromosomes is first seen in?

Accepted Answer

Secondary spermatocyte

Answer

Spermatogonia

Answer

Primary spermatocytes

Answer

Spermatids

NEET-PG 2012

Anatomy

Biochemistry

Orthopaedics

Physiology