Systemic Anatomy — MCQs

Systemic Anatomy Indian Medical PG Practice Questions and MCQs

Question 261: What is the average number of lobes in a human breast?

A. 5
B. 10
C. 15 (Correct Answer)
D. 20

Explanation: ***15*** - Historically, the human breast was described as containing **15 to 20 lobes**, each being a functionally distinct unit for milk production arranged radially around the nipple [1]. - This was the accepted anatomical teaching at the time of this examination. - **Note:** Modern imaging studies (MRI, ultrasound) have since shown that breasts typically contain **7-10 ductal systems/lobes** rather than 15-20, representing an important update to classical anatomy teaching. *5* - This number is too low and does not represent either the classical (15-20) or modern (7-10) understanding of breast lobe anatomy. - Insufficient to account for the complexity of the mammary ductal system. *10* - This represents the **upper range of modern anatomical understanding** (7-10 lobes based on current imaging studies). - While anatomically accurate by today's standards, the classical teaching referenced in this examination specified 15-20 lobes as average. *20* - Represents the **upper limit** of the classical range (15-20 lobes) [1]. - While within the historical normal range, **15 is considered the more typical average** in classical anatomy texts. - Modern research indicates this number significantly overestimates the actual lobe count.

Question 262: Azygos vein drains into:

A. Right subcostal vein
B. Right ascending lumbar vein
C. Superior vena cava (Correct Answer)
D. Brachiocephalic

Explanation: ***Superior vena cava*** - The **azygos vein** is a major venous channel that drains the walls of the thorax and abdomen, emptying directly into the **superior vena cava (SVC)**. [1] - This connection is crucial for venous return from the posterior thoracic wall, pericardium, and bronchi, especially bypassing the inferior vena cava if it's obstructed. [1] *Right subcostal vein* - The right subcostal vein is a tributary that helps form the **azygos vein**; it does not receive drainage from the azygos vein. - It contributes to the initial formation of the azygos system, not its termination. *Brachiocephalic* - The **brachiocephalic veins** are formed by the union of the internal jugular and subclavian veins, and they merge to form the **superior vena cava**. - The azygos vein drains into the superior vena cava, not directly into the brachiocephalic veins. *Right ascending lumbar vein* - The **right ascending lumbar vein** is a major tributary that contributes to the formation of the **azygos vein** in the lumbar region. - It drains into the azygos system, illustrating its origin rather than its termination.

Question 263: Which of the following is the MAJOR tributary of the coronary sinus?

A. Anterior cardiac vein
B. Thebesian vein
C. Oblique vein of Marshall
D. Great cardiac vein (Correct Answer)

Explanation: ***Great cardiac vein*** - The **great cardiac vein** is the largest and most significant tributary, draining areas supplied by the **left main coronary artery** and its branches. - It runs in the **anterior interventricular groove**, accompanying the anterior interventricular artery, and then curves around the left side of the heart to empty into the coronary sinus. *Anterior cardiac vein* - The **anterior cardiac veins** typically drain directly into the **right atrium**, bypassing the coronary sinus [1]. - They primarily drain the anterior surface of the **right ventricle**. *Thebesian vein* - The **Thebesian veins** (venae cordis minimae) are small veins that open directly into the **chambers of the heart**, not the coronary sinus. - They are responsible for a small amount of **physiological shunt** of deoxygenated blood into the left heart chambers. *Oblique vein of Marshall* - The **oblique vein of Marshall** (oblique vein of the left atrium) is a small vein originating from the posterior wall of the left atrium. - It is a **remnant of the left superior vena cava** and empties into the left extremity of the coronary sinus, but it is not considered the major tributary in terms of blood flow volume.

Question 264: Which of the following statements about the anatomy of the right ventricle is correct?

A. TV & PV Share fibrous continuity
B. More prominent trabeculation
C. The crista supraventricularis separates the tricuspid and pulmonary valves, and the apex is trabeculated (Correct Answer)
D. All of the options

Explanation: The crista supraventricularis separates the tricuspid and pulmonary valves, and the apex is trabeculated - The **crista supraventricularis** (also known as the supraventricular crest) is a prominent muscular ridge that separates the **inflow tract** (tricuspid valve region) from the **outflow tract** (pulmonary valve region) in the right ventricle. - The **apex and trabecular portion** of the right ventricle contains prominent **trabeculae carneae**, which are irregular muscular ridges and columns. - This option is correct as it describes two key anatomical features: the structural separator between valves and the trabeculated apex. *TV & PV Share fibrous continuity* - This statement is **anatomically incorrect** for the right ventricle. - The **tricuspid valve** and **pulmonary valve** do NOT share fibrous continuity; they are separated by the **crista supraventricularis** (muscular ridge). - **Fibrous continuity** (mitral-aortic continuity) is a characteristic feature of the **left heart**, where the anterior mitral leaflet is continuous with the aortic valve, but this does NOT occur in the right ventricle. *More prominent trabeculation* - While this statement is **anatomically true** (the right ventricle has more prominent trabeculation than the left ventricle, which has a smoother wall), this option is **incomplete** when compared to the correct answer. - The question asks for the correct statement about right ventricle anatomy, and option 3 provides a **more comprehensive description** that includes both a unique structural landmark (crista supraventricularis) and the trabeculation feature. - In single-best-answer format, the most complete and specific option is preferred. *All of the options* - This option is incorrect because the statement "TV & PV Share fibrous continuity" is anatomically false. - Since not all options are correct, this cannot be the answer.

Question 265: Superior pancreaticoduodenal artery is a branch of?

A. Hepatic artery
B. Splenic artery
C. Gastroduodenal artery (Correct Answer)
D. Inferior mesenteric artery

Explanation: ***Gastroduodenal artery*** - The **gastroduodenal artery** is a direct branch of the **common hepatic artery** [1], and it gives rise to the **superior pancreaticoduodenal artery**. - This artery is crucial for supplying blood to the **head of the pancreas** and the **duodenum**, forming an anastomosis with the inferior pancreaticoduodenal artery. *Hepatic artery* - The **hepatic artery** (specifically the common hepatic artery) gives rise to the gastroduodenal artery [1], but it does not *directly* give rise to the superior pancreaticoduodenal artery. - The common hepatic artery primarily supplies the **liver**, gallbladder, pylorus, and duodenum [1]. *Splenic artery* - The **splenic artery** is a branch of the celiac trunk that supplies the **spleen**, part of the pancreas, and greater curvature of the stomach via short gastric arteries and the left gastro-omental artery [1]. - It does not directly give rise to the superior pancreaticoduodenal artery. *Inferior mesenteric artery* - The **inferior mesenteric artery** is a major artery that supplies the distal third of the **transverse colon**, descending colon, sigmoid colon, and rectum. - It arises directly from the **abdominal aorta** significantly lower than the celiac trunk branches and is not involved in supplying the pancreas or duodenum directly via the superior pancreaticoduodenal artery.

Question 266: Inferior pancreaticoduodenal artery is a branch of which of the following arteries?

A. Splenic artery
B. Left gastric artery
C. Gastroduodenal artery
D. Superior mesenteric artery (Correct Answer)

Explanation: ***Superior mesenteric artery*** - The **inferior pancreaticoduodenal artery** is a direct branch of the **superior mesenteric artery (SMA)**. - It supplies the **head of the pancreas** and the **duodenum**, anastomosing with branches from the gastroduodenal artery. *Splenic artery* - The splenic artery is a branch of the **celiac trunk** and primarily supplies the **spleen**, stomach, and pancreas (via pancreatic branches). - It does not give rise to the inferior pancreaticoduodenal artery. *Left gastric artery* - The left gastric artery is a branch of the **celiac trunk** and supplies the **lesser curvature of the stomach** and distal esophagus. - It has no direct connection to the inferior pancreaticoduodenal artery. *Gastroduodenal artery* - The gastroduodenal artery is a branch of the **common hepatic artery** (from the celiac trunk) and gives off the **anterior and posterior superior pancreaticoduodenal arteries**. - While it supplies the head of the pancreas and duodenum, it is not the origin of the inferior pancreaticoduodenal artery, which arises from the SMA.

Question 267: Which of the following statements about the blood supply of the kidney is NOT true?

A. Right renal artery passes behind IVC
B. Branches of renal artery are end arteries
C. Renal vein drains into IVC
D. Renal artery is a branch of common iliac artery (Correct Answer)

Explanation: ***Renal artery is a branch of common iliac artery.*** - The **renal arteries** originate directly from the **abdominal aorta**, not the common iliac arteries. - The common iliac arteries branch subsequently from the **abdominal aorta** lower down to supply the pelvis and lower limbs. *Renal vein drains into IVC* - The **renal veins** are responsible for draining deoxygenated blood from the kidneys and typically empty directly into the **inferior vena cava (IVC)** [1]. - This is a correct anatomical relationship, essential for returning filtered blood to systemic circulation. *Right renal artery passes behind IVC* - The **right renal artery** typically originates from the aorta and passes **posterior to the inferior vena cava (IVC)** to reach the right kidney. - This anatomical arrangement is correct due to the position of the aorta and IVC relative to the kidneys. *Branches of renal artery are end arteries* - The intralobar and interlobar branches of the renal artery are considered **functional end arteries**, meaning they provide the sole blood supply to the kidney segments they perfuse. - This characteristic makes the kidney particularly susceptible to **ischemic damage** if these arteries are occluded, as there is little to no collateral circulation.

Question 268: Which of the following does not directly drain into right atrium?

A. Inferior vena cava
B. Great cardiac vein (Correct Answer)
C. Anterior cardiac vein
D. Venae cordis minimi

Explanation: ***Great cardiac vein*** - The **great cardiac vein** drains into the **coronary sinus**, which then empties into the right atrium [1]. - It does not drain directly into the right atrium, distinguishing it from the other options. *Inferior vena cava* - The **inferior vena cava** is one of the major vessels that drains directly into the **right atrium**. - It carries deoxygenated blood from the lower body to the right atrium. *Anterior cardiac vein* - The **anterior cardiac veins** drain directly into the **right atrium**. - They tend to drain the anterior surface of the right ventricle. *Venae cordis minimi* - Also known as **Thebesian veins**, these are small veins that drain directly into the cardiac chambers, including the **right atrium**. - They represent a direct communication between the myocardial capillaries and the cardiac chambers.

Question 269: Which vein is found at the apex of the heart?

A. Coronary sinus
B. Anterior cardiac vein
C. Middle cardiac vein
D. Great cardiac vein (Correct Answer)

Explanation: ***Great cardiac vein*** - The **great cardiac vein** originates near the **apex of the heart** and ascends in the anterior interventricular groove. - It drains blood from the anterior aspects of both ventricles and the left atrium. *Coronary sinus* - The **coronary sinus** is a large venous structure located on the posterior surface of the heart, not at the apex. - It receives most of the venous blood from the myocardium and empties into the right atrium. *Anterior cardiac vein* - The **anterior cardiac veins** typically run across the anterior surface of the right ventricle and drain directly into the right atrium, bypassing the coronary sinus. - They are generally smaller and not found at the apex of the heart. *Middle cardiac vein* - The **middle cardiac vein** runs in the posterior interventricular groove, on the diaphragmatic surface of the heart. - It originates near the apex but on the posterior aspect, making it primarily a posterior vessel.

Question 270: Which are the segments of the upper lobe of the right lung?

A. Lateral, medial, superior
B. Apical, anterior, posterior (Correct Answer)
C. Basal, medial, lateral
D. Anterior, posterior, medial

Explanation: ***Apical, anterior, posterior*** - The **right upper lobe** is consistently divided into three bronchopulmonary segments: **apical**, **anterior**, and **posterior** [1]. - These segments are named according to their anatomical position and the branching of the **tertiary bronchi** that supply them [1]. *Anterior, posterior, medial* - While **anterior** and **posterior** segments exist, the "medial" segment is not a standard division of the right upper lobe. - The term "medial" is typically associated with the **middle lobe** of the right lung (medial and lateral segments) [1]. *Lateral, medial, superior* - The segments **lateral** and **medial** are characteristic of the **right middle lobe** [1]. - "Superior" is a general directional term and not a specific segment name within the upper lobe in this context, although the apical segment is superiorly located. *Basal, medial, lateral* - **Basal** segments are found in the **lower lobes** of the lungs (e.g., anterior basal, medial basal, posterior basal, lateral basal). - **Medial** and **lateral** segments are typical of the **right middle lobe**, not the upper lobe [1].

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