NEET-PG 2015 - Anatomy Practice Questions

Q: What structures are derived from the neural crest?

All of the options. ***All of the options*** - The **neural crest** is a multipotent, migratory cell population that contributes to the formation of many diverse tissues and organs during vertebrate development. - Neural crest cells give rise to a wide array of derivatives, including components of the nervous system, pigment cells, skeletal and connective tissues of the head and face, and endocrine glands [1]. *Melanocytes* - **Melanocytes**, the pigment-producing cells found in the skin, hair, eyes, and other tissues, are derived from the **neural crest** [2]. - These cells migrate extensively during development from the neural crest to their final destinations throughout the body. - Neural crest-derived melanocytes produce melanin, which provides pigmentation and protection against UV radiation [2]. *Dental papillae* - The **dental papilla** is crucial for tooth development and is formed from **ectomesenchymal cells** that are derived from the cranial neural crest. - These cells differentiate into the odontoblasts that produce dentin and also contribute to the pulp of the tooth. *Adrenal medulla* - The cells of the **adrenal medulla**, which produce catecholamines like epinephrine and norepinephrine, are specialized **postganglionic sympathetic neurons** derived from the neural crest. - They develop from neuroectodermal cells that migrate to the developing adrenal gland.

Q: Heart tube is formed in a gelatinous matrix rich in:

Hyaluronic acid secreted by the myocardium. ***Hyaluronic acid secreted by the myocardium*** - The developing **heart tube** forms within a gelatinous extracellular matrix that is rich in **hyaluronic acid**. - This **hyaluronic acid** is secreted by the **myocardium** (the developing heart muscle), which plays a crucial role in the initial formation and remodeling of the heart. *Hyaluronic acid secreted by the endocardium* - While the endocardium is an important layer of the heart, it is the **myocardium** that primarily secretes the **hyaluronic acid** critical for heart tube formation during early development. - The **endocardium** forms the inner lining and primarily acts in blood-tissue interaction and valvular development later on. *Chondroitin sulfate secreted by the endocardium* - **Chondroitin sulfate** is a component of the extracellular matrix, but it is not the primary proteoglycan responsible for the initial formation environment of the heart tube. - Furthermore, its secretion is not predominantly from the **endocardium** in this context. *Chondroitin sulfate secreted by the myocardium* - Although the myocardium is responsible for secreting extracellular matrix components, **chondroitin sulfate** is not the predominant or critical molecule responsible for the initial gelatinous matrix allowing heart tube formation. - **Hyaluronic acid** plays this key role in early cardiogenesis.

Q: What is the remnant of the umbilical artery?

Medial umbilical ligament. ***Medial umbilical ligament*** - The **umbilical arteries** (paired structures) carry deoxygenated blood from the fetus to the placenta during development [2]. - After birth, these arteries obliterate and persist as the **medial umbilical ligaments** (two in number, one on each side), extending from the internal iliac arteries to the umbilicus along the anterior abdominal wall. - The proximal portions of the umbilical arteries remain patent as the **superior vesical arteries**, which supply the bladder. *Ligamentum arteriosum* - This is the remnant of the **ductus arteriosus**, which shunted blood from the pulmonary artery to the aorta, bypassing the fetal lungs [2]. - It connects the arch of the aorta to the pulmonary artery. *Ligament teres* - Also known as the **round ligament of the liver**, this is the remnant of the **fetal umbilical vein** (a single midline structure) [1]. - The umbilical vein carried oxygenated blood from the placenta to the fetus [1], [2]. *Ligamentum venosum* - This is the fibrous remnant of the **ductus venosus**, a shunt in fetal circulation that bypassed the liver by connecting the umbilical vein to the inferior vena cava [1]. - It is located deep within the liver, forming a fissure.

Q: Which of the following is a derivative of paramesonephric duct in males ?

Prostatic utricle. ***Prostatic utricle*** - The **prostatic utricle** is a blind-ending pouch located in the prostatic urethra. - It represents a **rudimentary derivative of the paramesonephric (Müllerian) duct** in males, which normally regresses due to the presence of Müllerian-inhibiting substance (MIS). *Trigone of bladder* - The trigone of the bladder is derived from the caudal ends of the **mesonephric ducts** (Wolffian ducts), not the paramesonephric ducts. - It forms through the incorporation of these ducts into the posterior wall of the bladder. *Paraphoron* - The **paraphoron** is a vestigial structure found in females, representing remnants of the caudal parts of the **epoophoron tubules**. - These are derived from the **mesonephric tubules**, not the paramesonephric ducts, and are not found in males. *Gartner's duct* - **Gartner's duct** is a remnant of the **mesonephric (Wolffian) duct** in females, typically running along the lateral wall of the vagina or uterus. - It is not found in males and is derived from a different embryonic structure than the paramesonephric duct.

Q: Which of the following statements about the limbus fossa ovalis is false?

Derived from septum primum. ***Derived from septum primum*** - The **limbus fossa ovalis** (or annulus ovalis) is a structure in the right atrium that forms the prominent rim of the **fossa ovalis**. - It is derived from the inferior border of the **septum secundum**, not the septum primum, which primarily forms the floor of the fossa ovalis. *Forms the rim around fossa ovalis* - The **limbus fossa ovalis** is indeed the thickened, crescent-shaped border of tissue that surrounds the **fossa ovalis** in the interatrial septum. - This anatomical arrangement is a remnant of the **foramen ovale** from fetal circulation [1]. *In right atrium* - The **fossa ovalis** and its surrounding limbus are located on the septal wall of the **right atrium** [1]. - This position is crucial for its role as a key landmark in interatrial septum anatomy. *Also called Annulus ovalis* - The term **annulus ovalis** is a widely accepted synonym for the **limbus fossa ovalis**. - Both terms describe the same anatomical structure, the fibrous rim surrounding the fossa ovalis.

Q: Which of the following structures does not pass through the superior thoracic aperture?

Right recurrent laryngeal nerve. ***Right recurrent laryngeal nerve*** - The **right recurrent laryngeal nerve** loops around the **right subclavian artery** in the neck [1] and ascends into the neck to innervate the larynx. - It does not descend into the thorax before recurring, thus it does not pass through the superior thoracic aperture [1]. *Right vagus* - The **right vagus nerve** passes through the superior thoracic aperture anterior to the right subclavian artery and enters the thorax. - It then descends posterior to the right brachiocephalic vein and superior vena cava before supplying thoracic and abdominal viscera. *Right brachiocephalic artery* - The **right brachiocephalic artery** (also known as the brachiocephalic trunk) is the first branch of the aortic arch and passes superiorly through the superior thoracic aperture. - It gives rise to the right common carotid artery and right subclavian artery in the neck. *Thoracic duct* - The **thoracic duct** ascends from the abdomen through the posterior mediastinum, passes through the superior thoracic aperture to enter the neck [2]. - In the neck, it arches laterally and empties into the left subclavian vein, or the junction of the left internal jugular and subclavian veins.

Q: Which nerve roots are primarily involved in Erb's palsy?

C5, C6. C5, C6 - **Erb's palsy** primarily involves injury to the **upper trunk of the brachial plexus**, which is formed by the ventral rami of **C5 and C6** spinal nerves. - This lesion results in a characteristic "waiter's tip" posture due to paralysis of muscles supplied by these nerve roots, including the **deltoid**, **biceps**, and **brachialis**. *C4, C5* - While C5 is involved, **C4** is typically associated with the **phrenic nerve** and diaphragm function, and its primary involvement is not characteristic of Erb's palsy. - Injury to C4 and C5 alone would not produce the comprehensive motor deficits seen in Erb's palsy involving shoulder and elbow flexion. *C5, C7* - This option includes C5 but also **C7**, which is more commonly associated with the **middle trunk** of the brachial plexus. - While C7 can be involved in extended brachial plexus injuries, its primary involvement alone is not the classic presentation of Erb's palsy. *C6, C8* - This combination includes C6 but introduces **C8**, which is part of the **lower trunk** of the brachial plexus. - Injuries involving C8 and T1 are characteristic of **Klumpke's palsy**, affecting intrinsic hand muscles and causing a "claw hand" deformity, which is distinct from Erb's palsy.

Q: Root value of the thoracodorsal nerve

C6, C7, C8. ***C6, C7, C8*** - The **thoracodorsal nerve**, also known as the middle subscapular nerve, originates from the **posterior cord of the brachial plexus**. - Its specific root values are **C6, C7, and C8**, which supply motor innervation to the **latissimus dorsi muscle** [1]. - This nerve is one of the three subscapular nerves arising from the posterior cord [1]. *C5, C6, C7* - While these roots contribute to the **posterior cord**, the thoracodorsal nerve specifically arises from **C6, C7, C8**. - **C5** primarily contributes to the **upper and middle trunk** and is more associated with nerves like the **suprascapular** and **axillary nerves**. *C6, T1* - These root values contribute to various nerves of the **brachial plexus**, but not specifically the thoracodorsal nerve. - **T1** contributes mainly to the **medial cord** and its branches like the **ulnar nerve**, not the posterior cord from which the thoracodorsal nerve arises. *T1, T2* - These are typical root values for **intercostal nerves** and contribute to the **sympathetic trunk**, not the **brachial plexus** or its branches like the thoracodorsal nerve. - The brachial plexus predominantly arises from **C5 to T1 spinal nerve roots**, and **T2** is not part of the brachial plexus.

Q: Teres minor is supplied by

Axillary nerve. ***Axillary nerve*** - The **axillary nerve** (C5-C6) innervates both the **teres minor** and the **deltoid muscle**. - It arises from the posterior cord of the brachial plexus and traverses the quadrangular space. *Suprascapular nerve* - The **suprascapular nerve** (C5-C6) primarily supplies the **supraspinatus** and **infraspinatus** muscles. - It plays a crucial role in shoulder abduction and external rotation, but not directly in teres minor function. *Lower subscapular nerve* - The **lower subscapular nerve** (C5-C6) innervates the **subscapularis muscle** and **teres major**. - Teres major and teres minor are anatomically adjacent but have different innervations and functions. *Thoracodorsal nerve* - The **thoracodorsal nerve** (C6-C8) innervates the **latissimus dorsi muscle** [1]. - This nerve is distinct from those supplying the rotator cuff muscles, including teres minor.

Q: Insertion of levator scapulae is?

Superior part of medial scapula border. ***Superior part of medial scapula border*** - The **levator scapulae muscle** originates from the **transverse processes of C1-C4 vertebrae** and **inserts** onto the superior part of the medial border of the scapula, between the **superior angle and the spine of the scapula**. - Its main actions are to **elevate** and **rotate** the scapula downward. *Lateral border of scapula* - The **lateral border of the scapula** primarily serves as the attachment site for muscles that move the **humerus**, such as the **teres major** and **teres minor**. - The levator scapulae has no direct insertion on the lateral border. *Suprolateral part of scapula* - This general description is vague and does not precisely identify the insertion point of the levator scapulae. - While it's located superiorly, the specific insertion is on the **medial border**, not broadly "suprolateral." *Inferior angle of scapula* - The **inferior angle of the scapula** is the insertion point for muscles like the **latissimus dorsi** (occasionally) and a key landmark for muscles involved in **scapular rotation**, such as the **serratus anterior**. - The levator scapulae is located much more superiorly and inserts onto the medial border at a higher level than the inferior angle.

Question 1

What structures are derived from the neural crest?

Accepted Answer

All of the options

Answer

Melanocytes

Answer

Dental papillae

Answer

Adrenal medulla

Question 2

Heart tube is formed in a gelatinous matrix rich in:

Accepted Answer

Hyaluronic acid secreted by the myocardium

Answer

Hyaluronic acid secreted by the endocardium

Answer

Chondroitin sulfate secreted by the endocardium

Answer

Chondroitin sulfate secreted by the myocardium

Question 3

What is the remnant of the umbilical artery?

Accepted Answer

Medial umbilical ligament

Answer

Ligamentum arteriosum

Answer

Ligament teres

Answer

Ligamentum venosum

Question 4

Which of the following is a derivative of paramesonephric duct in males ?

Accepted Answer

Prostatic utricle

Answer

Trigone of bladder

Answer

Paraphoron

Answer

Gartner's duct

Question 5

Which of the following statements about the limbus fossa ovalis is false?

Accepted Answer

Derived from septum primum

Answer

Also called Annulus ovalis

Answer

In right atrium

Answer

Forms the rim around fossa ovalis

Question 6

Which of the following structures does not pass through the superior thoracic aperture?

Accepted Answer

Right recurrent laryngeal nerve

Answer

Right vagus

Answer

Right brachiocephalic artery

Answer

Thoracic duct

Question 7

Which nerve roots are primarily involved in Erb's palsy?

Accepted Answer

C5, C6

Answer

C4, C5

Answer

C5, C7

Answer

C6, C8

Question 8

Root value of the thoracodorsal nerve

Accepted Answer

C6, C7, C8

Answer

T1, T2

Answer

C5, C6, C7

Answer

C6, T1

Question 9

Teres minor is supplied by

Accepted Answer

Axillary nerve

Answer

Suprascapular nerve

Answer

Lower subscapular nerve

Answer

Thoracodorsal nerve

Question 10

Insertion of levator scapulae is?

Accepted Answer

Superior part of medial scapula border

Answer

Lateral border of scapula

Answer

Suprolateral part of scapula

Answer

Inferior angle of scapula

NEET-PG 2015 — Anatomy