NEET-PG 2013 — Anatomy

Q: Terminal branches of the internal carotid artery are all except?

Ophthalmic artery. ***Ophthalmic artery*** - The **ophthalmic artery** is a **branch** (not a terminal branch) of the internal carotid artery that arises shortly after the ICA emerges from the cavernous sinus. - It enters the orbit through the optic canal to supply the eye, orbit, and surrounding structures. - Terminal branches are the **final divisions** of a vessel, not branches that arise earlier in its course. *Anterior cerebral artery* - The **anterior cerebral artery (ACA)** is one of the **two terminal branches** of the internal carotid artery. - It supplies the medial surfaces of the frontal and parietal lobes. - It arises at the terminal bifurcation of the ICA in the supraclinoid region. *Middle cerebral artery* - The **middle cerebral artery (MCA)** is the other **terminal branch** of the internal carotid artery. - It is the larger of the two terminal branches and supplies the lateral surfaces of the cerebral hemispheres. - It supplies critical areas including the motor and sensory cotices. *Posterior communicating artery* - The **posterior communicating artery (PCoA)** arises near the terminal bifurcation of the ICA and connects it to the posterior cerebral artery. - While technically a branch (not terminal), it arises very close to the terminal bifurcation point. - It is part of the circle of Willis, providing collateral circulation between anterior and posterior cerebral circulation. [Practice more Anatomy PYQs on OnCourse]

Q: Boundaries of the anatomical snuff box are all except

ECU. ***ECU*** - The **extensor carpi ulnaris (ECU)** is not a boundary of the anatomical snuff box. Its tendon inserts into the base of the 5th metacarpal, medial to the snuffbox [1][2]. - The ECU's function is **wrist extension** and **ulnar deviation**, and it does not form part of the snuffbox's borders [1]. *APL* - The **abductor pollicis longus (APL)** tendon forms the **anterior (radial) boundary** of the anatomical snuff box [1][2]. - It inserts into the base of the 1st metacarpal and is responsible for **abducting the thumb** [1]. *EPL* - The **extensor pollicis longus (EPL)** tendon forms the **posterior (ulnar) boundary** of the anatomical snuff box [1][2]. - It inserts into the distal phalanx of the thumb and is responsible for **extending the thumb interphalangeal joint**. *EPB* - The **extensor pollicis brevis (EPB)** tendon forms part of the **anterior (radial) boundary** along with the APL [1][2]. - It inserts into the proximal phalanx of the thumb and aids in **extending the thumb metacarpophalangeal joint** [1]. [Practice more Anatomy PYQs on OnCourse]

Q: Attachment of the vitreous is strongest at?

Across ora serrata. ***Across ora serrata*** - The **vitreous base** is a 3-4 mm wide circumferential band extending approximately 2 mm anterior and 2 mm posterior to the **ora serrata**, where the vitreous firmly adheres to the **non-pigmented ciliary epithelium** and the **peripheral retina**. - This strong adhesion makes the **vitreous base** the primary point of vitreous attachment, often remaining attached even during significant vitreous detachments. *Foveal region* - While there is some attachment, the vitreous is typically **less firmly adherent** to the foveal region compared to the vitreous base. - Vitreous detachment from the fovea is a common event, rarely leading to significant tearing or strong adherence. *Back of lens* - The vitreous has a weak attachment to the posterior capsule of the lens, known as the **Wieger's ligament** or **hyaloideocapsular ligament**. - This attachment typically **loses strength with age** and is not the strongest overall point of attachment. *Margin of optic disc* - The vitreous attaches to the margin of the optic disc, forming a circular adhesion called the **peripapillary ring**. - This attachment is **less strong** than the vitreous base and is often the first region from which the vitreous detaches during a **posterior vitreous detachment (PVD)**. [Practice more Anatomy PYQs on OnCourse]

Q: Follicles are present in which part of lymph nodes?

Cortex. ***Cortex*** - The **cortex** of a lymph node contains lymphoid follicles, which are sites of **B cell proliferation** and differentiation. - These follicles can be primary (inactive) or secondary (active, with a **germinal center**) based on ongoing immune responses. *Red pulp* - The **red pulp** is a component of the **spleen**, not lymph nodes. - It is primarily involved in filtering blood, removing old or damaged red blood cells, and storing monocytes. *White pulp* - The **white pulp** is also a component of the **spleen**, organized around central arterioles. - It contains periarteriolar lymphoid sheaths (PALS) with T cells and lymphoid follicles with B cells. *Medulla* - The **medulla** of a lymph node is the central region, rich in **medullary cords** (containing plasma cells, macrophages, and B cells) and **medullary sinuses**. - While lymphocytes are present, the organized structures of follicles are characteristic of the cortex. [Practice more Anatomy PYQs on OnCourse]

Q: Pubic symphysis is which type of joint?

Secondary cartilaginous. ***Secondary cartilaginous*** - The **pubic symphysis** is a classic example of a **secondary cartilaginous joint**, also known as a **symphysis**. - These joints are characterized by a plate of **fibrocartilage** sandwiched between two layers of hyaline cartilage, uniting two bones and allowing for limited movement. *Gomphosis* - A **gomphosis** is a type of **fibrous joint** where a peg-like process fits into a socket, primarily found in the attachment of teeth to their sockets in the jaw. - It is distinct from the cartilaginous structure of the pubic symphysis. *Fibrous joint* - While fibrous joints are characterized by fibrous connective tissue connecting bones, this category is too broad, and doesn't specify the unique cartilaginous nature of the pubic symphysis. - Examples include sutures in the skull, syndesmoses, and gomphoses, none of which fit the structure of the pubic symphysis. *Primary cartilaginous* - A **primary cartilaginous joint**, or **synchondrosis**, involves bones united by **hyaline cartilage**, like the epiphyseal plates of growing bones. - These joints are typically temporary and eventually ossify, or they allow for very restricted movement, unlike the fibrocartilage and slight movement of the pubic symphysis. [Practice more Anatomy PYQs on OnCourse]

111 Previous Year Questions with Answers & Explanations

111

Questions

Terminal branches of the internal carotid artery are all except?

Boundaries of the anatomical snuff box are all except

Attachment of the vitreous is strongest at?

Follicles are present in which part of lymph nodes?

Pubic symphysis is which type of joint?

The cardiac jelly formed around the heart tube during early development contributes to the formation of:

Mastoid process is which type of epiphysis?

Which muscle is derived from the third pharyngeal arch?

Double inferior vena cava is formed due to?

Q10

At which level do the somites initially form?

NEET-PG 2013 - Anatomy NEET-PG Practice Questions and MCQs

Question 1: Terminal branches of the internal carotid artery are all except?

A. Anterior cerebral artery
B. Ophthalmic artery (Correct Answer)
C. Middle cerebral artery
D. Posterior communicating artery

Explanation: ***Ophthalmic artery*** - The **ophthalmic artery** is a **branch** (not a terminal branch) of the internal carotid artery that arises shortly after the ICA emerges from the cavernous sinus. - It enters the orbit through the optic canal to supply the eye, orbit, and surrounding structures. - Terminal branches are the **final divisions** of a vessel, not branches that arise earlier in its course. *Anterior cerebral artery* - The **anterior cerebral artery (ACA)** is one of the **two terminal branches** of the internal carotid artery. - It supplies the medial surfaces of the frontal and parietal lobes. - It arises at the terminal bifurcation of the ICA in the supraclinoid region. *Middle cerebral artery* - The **middle cerebral artery (MCA)** is the other **terminal branch** of the internal carotid artery. - It is the larger of the two terminal branches and supplies the lateral surfaces of the cerebral hemispheres. - It supplies critical areas including the motor and sensory cotices. *Posterior communicating artery* - The **posterior communicating artery (PCoA)** arises near the terminal bifurcation of the ICA and connects it to the posterior cerebral artery. - While technically a branch (not terminal), it arises very close to the terminal bifurcation point. - It is part of the circle of Willis, providing collateral circulation between anterior and posterior cerebral circulation.

Question 2: Boundaries of the anatomical snuff box are all except

A. ECU (Correct Answer)
B. APL
C. EPL
D. EPB

Explanation: ***ECU*** - The **extensor carpi ulnaris (ECU)** is not a boundary of the anatomical snuff box. Its tendon inserts into the base of the 5th metacarpal, medial to the snuffbox [1][2]. - The ECU's function is **wrist extension** and **ulnar deviation**, and it does not form part of the snuffbox's borders [1]. *APL* - The **abductor pollicis longus (APL)** tendon forms the **anterior (radial) boundary** of the anatomical snuff box [1][2]. - It inserts into the base of the 1st metacarpal and is responsible for **abducting the thumb** [1]. *EPL* - The **extensor pollicis longus (EPL)** tendon forms the **posterior (ulnar) boundary** of the anatomical snuff box [1][2]. - It inserts into the distal phalanx of the thumb and is responsible for **extending the thumb interphalangeal joint**. *EPB* - The **extensor pollicis brevis (EPB)** tendon forms part of the **anterior (radial) boundary** along with the APL [1][2]. - It inserts into the proximal phalanx of the thumb and aids in **extending the thumb metacarpophalangeal joint** [1].

Question 3: Attachment of the vitreous is strongest at?

A. Foveal region
B. Back of lens
C. Across ora serrata (Correct Answer)
D. Margin of optic disc

Explanation: ***Across ora serrata*** - The **vitreous base** is a 3-4 mm wide circumferential band extending approximately 2 mm anterior and 2 mm posterior to the **ora serrata**, where the vitreous firmly adheres to the **non-pigmented ciliary epithelium** and the **peripheral retina**. - This strong adhesion makes the **vitreous base** the primary point of vitreous attachment, often remaining attached even during significant vitreous detachments. *Foveal region* - While there is some attachment, the vitreous is typically **less firmly adherent** to the foveal region compared to the vitreous base. - Vitreous detachment from the fovea is a common event, rarely leading to significant tearing or strong adherence. *Back of lens* - The vitreous has a weak attachment to the posterior capsule of the lens, known as the **Wieger's ligament** or **hyaloideocapsular ligament**. - This attachment typically **loses strength with age** and is not the strongest overall point of attachment. *Margin of optic disc* - The vitreous attaches to the margin of the optic disc, forming a circular adhesion called the **peripapillary ring**. - This attachment is **less strong** than the vitreous base and is often the first region from which the vitreous detaches during a **posterior vitreous detachment (PVD)**.

Question 4: Follicles are present in which part of lymph nodes?

A. Red pulp
B. White pulp
C. Medulla
D. Cortex (Correct Answer)

Explanation: ***Cortex*** - The **cortex** of a lymph node contains lymphoid follicles, which are sites of **B cell proliferation** and differentiation. - These follicles can be primary (inactive) or secondary (active, with a **germinal center**) based on ongoing immune responses. *Red pulp* - The **red pulp** is a component of the **spleen**, not lymph nodes. - It is primarily involved in filtering blood, removing old or damaged red blood cells, and storing monocytes. *White pulp* - The **white pulp** is also a component of the **spleen**, organized around central arterioles. - It contains periarteriolar lymphoid sheaths (PALS) with T cells and lymphoid follicles with B cells. *Medulla* - The **medulla** of a lymph node is the central region, rich in **medullary cords** (containing plasma cells, macrophages, and B cells) and **medullary sinuses**. - While lymphocytes are present, the organized structures of follicles are characteristic of the cortex.

Question 5: Pubic symphysis is which type of joint?

A. Gomphosis
B. Fibrous joint
C. Primary cartilaginous
D. Secondary cartilaginous (Correct Answer)

Explanation: ***Secondary cartilaginous*** - The **pubic symphysis** is a classic example of a **secondary cartilaginous joint**, also known as a **symphysis**. - These joints are characterized by a plate of **fibrocartilage** sandwiched between two layers of hyaline cartilage, uniting two bones and allowing for limited movement. *Gomphosis* - A **gomphosis** is a type of **fibrous joint** where a peg-like process fits into a socket, primarily found in the attachment of teeth to their sockets in the jaw. - It is distinct from the cartilaginous structure of the pubic symphysis. *Fibrous joint* - While fibrous joints are characterized by fibrous connective tissue connecting bones, this category is too broad, and doesn't specify the unique cartilaginous nature of the pubic symphysis. - Examples include sutures in the skull, syndesmoses, and gomphoses, none of which fit the structure of the pubic symphysis. *Primary cartilaginous* - A **primary cartilaginous joint**, or **synchondrosis**, involves bones united by **hyaline cartilage**, like the epiphyseal plates of growing bones. - These joints are typically temporary and eventually ossify, or they allow for very restricted movement, unlike the fibrocartilage and slight movement of the pubic symphysis.

Question 6: The cardiac jelly formed around the heart tube during early development contributes to the formation of:

A. Pericardium
B. Mesocardium
C. Myocardium
D. Endocardium (Correct Answer)

Explanation: Endocardium (Endocardial Cushions/Valves/Septa) - The **cardiac jelly** is an acellular, gelatinous matrix rich in **hyaluronic acid** that lies between the endocardium and the primordial myocardium during early heart development. - It undergoes **endothelial-to-mesenchymal transformation (EMT)** to form the **endocardial cushions** [1]. - These cushions are critical for forming: - **Atrioventricular (AV) valves** (mitral and tricuspid) [1] - **Semilunar valves** (aortic and pulmonary) [1] - **Cardiac septa** (portions of atrial, ventricular, and AV septa) [1] - While cardiac jelly doesn't form the endocardial lining itself (which is already present as endothelium), it forms the endocardial cushions that are essential endocardial derivatives. *Pericardium* - The **pericardium** develops from the **pleuropericardial folds** and **somatic and splanchnic mesoderm**, forming the fibrous and serous outer coverings of the heart. - It is completely distinct from cardiac jelly, which is an intra-cardiac structure. *Mesocardium* - The **dorsal mesocardium** is a transient mesentery that temporarily connects the developing heart tube to the dorsal wall of the pericardial cavity. - It rapidly degenerates by **day 22-23** to form the **transverse pericardial sinus**. - It does not contribute to cardiac jelly or any heart wall structures. *Myocardium* - The **myocardium** differentiates directly from the **splanchnic mesoderm** surrounding the endocardial tube. - It forms the muscular contractile layer of the heart wall. - Cardiac jelly lies between the endocardium and myocardium but does not form myocardial tissue.

Question 7: Mastoid process is which type of epiphysis?

A. Pressure epiphysis
B. Traction epiphysis (Correct Answer)
C. Atavistic epiphysis
D. Aberrant epiphysis

Explanation: Traction epiphysis - A traction epiphysis is an apophysis that does not contribute to the longitudinal growth of the bone but is located at the site of muscle attachment, serving to provide leverage for the muscle. - The mastoid process serves as an attachment point for various muscles, including the sternocleidomastoid, splenius capitis, and longissimus capitis, making it a classic example of a traction epiphysis. Pressure epiphysis - A pressure epiphysis is primarily responsible for the longitudinal growth of bone and is found at the ends of long bones, such as the femoral head or humeral head [1]. - The mastoid process does not contribute to longitudinal bone growth. Atavistic epiphysis - Atavistic epiphyses are those that are phylogenetically separate bones but become fused with the main bone during development, like the coracoid process of the scapula. - The mastoid process is an integral part of the temporal bone and is not considered a separate, phylogenetically distinct bone. Aberrant epiphysis - Aberrant epiphyses are variations that appear irregularly, are not always present, and do not have a consistent physiological role. - The mastoid process is a constant anatomical feature of the temporal bone in humans.

Question 8: Which muscle is derived from the third pharyngeal arch?

A. Tensor tympani
B. Stylopharyngeus (Correct Answer)
C. Cricothyroid
D. Stapedius

Explanation: ***Stylopharyngeus*** - The **stylopharyngeus muscle** is uniquely derived from the **third pharyngeal arch**. - It is innervated by the **glossopharyngeal nerve (CN IX)** and plays a role in elevating the pharynx and larynx during swallowing. - This is the **only muscle** derived from the third pharyngeal arch, making it a key anatomical landmark. *Tensor tympani* - The **tensor tympani muscle** is derived from the **first pharyngeal arch**. - It is innervated by the **mandibular nerve (V3)** and dampens sound by tensing the tympanic membrane. *Cricothyroid* - The **cricothyroid muscle** is derived from the **fourth and sixth pharyngeal arches**. - It is innervated by the **external branch of the superior laryngeal nerve (CN X)** and tenses the vocal cords. *Stapedius* - The **stapedius muscle** is derived from the **second pharyngeal arch**. - It is innervated by the **facial nerve (CN VII)** and dampens sound by stabilizing the stapes bone.

Question 9: Double inferior vena cava is formed due to?

A. Persistence of both supracardinal and subcardinal veins
B. Persistence of sacrocardinal veins
C. Persistence of subcardinal veins
D. Persistence of supracardinal veins (Correct Answer)

Explanation: ***Persistence of supracardinal veins*** - A double inferior vena cava (IVC) results from the **persistence of the left supracardinal vein**, which normally regresses. - This malformation causes the IVC to be duplicated below the level of the renal veins, creating two parallel venous channels ascending to join the normal IVC or renal veins. *Persistence of sacrocardinal veins* - The sacrocardinal veins are involved in the development of the **iliac veins** and the distal part of the IVC, but their independent persistence does not lead to a double IVC. - Abnormalities in sacrocardinal vein development are more commonly associated with conditions like **agenesis of the infrarenal IVC**. *Persistence of subcardinal veins* - The subcardinal veins mainly contribute to the formation of the **renal segment** of the IVC and the gonadal veins. - Their persistence or malformation can lead to a **retrocaval ureter** or other venous anomalies, but not a double IVC. *Persistence of both supracardinal and subcardinal veins* - While both supracardinal and subcardinal veins are crucial for IVC development, their **simultaneous persistence** in a way that creates a double IVC is not the direct mechanism [1]. - A double IVC is specifically attributed to the **persistence of the left supracardinal vein**, with the right supracardinal vein forming the normal right IVC [1].

Question 10: At which level do the somites initially form?

A. Lumbar level
B. Sacral level
C. Cervical level (Correct Answer)
D. Thoracic level

Explanation: Cervical level - Somites, which are segmented blocks of paraxial mesoderm, initially appear in the **occipital/cranial cervical region** of the developing embryo around day 20 of development. - The first somite pair forms at the **occipital level**, and subsequent somites develop in a **cranio-caudal sequence**. - Development proceeds both cranially (forming occipital somites) and caudally (forming cervical, thoracic, lumbar, and sacral somites) from this initial formation. - By the end of the 5th week, approximately **42-44 somite pairs** are present. *Thoracic level* - Thoracic somites form subsequent to the initial occipital/cervical somites, as the segmentation process extends caudally. - The formation of somites is a sequential process along the **cranio-caudal axis**. *Lumbar level* - Lumbar somites develop later in the embryological timeline, after the cervical and thoracic regions have undergone somite formation. - The **caudal regions** receive somites progressively as development continues. *Sacral level* - Sacral somites are among the last to form, representing the caudal extent of somite development. - Their formation follows the cranio-caudal progression of somite appearance.