Abdomen — MCQs

Abdomen Indian Medical PG Practice Questions and MCQs

Question 531: The left gastric artery is a branch of which of the following?

A. Splenic artery (Correct Answer)
B. Left gastroduodenal artery
C. Left gastroepiploic artery
D. Portal vein

Explanation: The **Celiac Trunk** is the primary artery supplying the foregut. It arises from the abdominal aorta at the level of T12 and divides into three main branches: the Left Gastric Artery, the Common Hepatic Artery, and the **Splenic Artery**. [1] The **Splenic Artery** is the largest branch of the celiac trunk. It follows a tortuous course along the superior border of the pancreas. Before reaching the hilum of the spleen, it gives off several branches, including the **short gastric arteries** and the **left gastroepiploic (gastro-omental) artery**. Therefore, the left gastroepiploic artery is a direct branch of the splenic artery. **Analysis of Options:** * **Option B (Left gastroduodenal artery):** This is a distractor. The gastroduodenal artery is a branch of the common hepatic artery and typically divides into the right gastroepiploic and superior pancreaticoduodenal arteries. * **Option C (Left gastroepiploic artery):** This is the vessel *being* branched, not the parent vessel. * **Option D (Portal vein):** This is a venous structure responsible for drainage, not arterial supply. [2] **NEET-PG High-Yield Pearls:** 1. **Tortuosity:** The splenic artery is the most tortuous artery in the body (to allow for gastric distension and splenic movement). 2. **Stomach Blood Supply:** The **lesser curvature** is supplied by the right and left gastric arteries, while the **greater curvature** is supplied by the right and left gastroepiploic arteries. 3. **Clinical Correlation:** In cases of gastric ulcers on the posterior wall of the stomach, the splenic artery is at risk of erosion, leading to massive hemorrhage.

Question 532: A 27-year-old woman has suffered a gunshot wound to her mid abdomen. After examining the patient's angiogram, a trauma surgeon locates the source of bleeding from pairs of veins that typically terminate in the same vein. Which of the following veins are damaged?

A. Left and right ovarian veins
B. Left and right gastroepiploic veins
C. Left and right colic veins
D. Left and right hepatic veins (Correct Answer)

Explanation: ***Left and right hepatic veins*** - Both the **left and right hepatic veins** drain directly into the **inferior vena cava (IVC)** at the same anatomical level, making them true pairs that terminate in the same vessel. - Located in the **mid-abdominal region** where the gunshot wound occurred, consistent with the clinical presentation and angiographic findings. *Left and right ovarian veins* - These veins have **asymmetric drainage patterns**: the right ovarian vein drains into the **IVC**, while the left ovarian vein drains into the **left renal vein**. - They do not terminate in the same vessel, making this option inconsistent with the question's description of paired veins with common termination. *Left and right gastroepiploic veins* - The **right gastroepiploic vein** drains into the **superior mesenteric vein (SMV)**, while the **left gastroepiploic vein** drains into the **splenic vein**. - These veins have different drainage pathways and do not terminate in the same vessel, ruling out this option. *Left and right colic veins* - The **right colic vein** typically drains into the **superior mesenteric vein (SMV)**, while the **left colic vein** drains into the **inferior mesenteric vein (IMV)**. - These vessels have distinct venous drainage systems and do not share a common termination point.

Question 533: Ureteric constructions are seen at all the following positions, EXCEPT:

A. Ureteropelvic junction
B. Ureterovesical junction
C. Crossing of iliac artery
D. Ischial spine (Correct Answer)

Explanation: The ureter is a muscular tube approximately 25 cm long that transports urine from the kidney to the bladder. Along its course, it exhibits specific areas of physiological narrowing. These sites are clinically significant as they are the most common locations for **ureteric calculi (stones)** to become impacted. ### Why "Ischial Spine" is the Correct Answer: While the ureter does pass near the ischial spine as it curves anteromedially to enter the bladder, this is **not** a site of physiological constriction. The ureter maintains its normal caliber at this level. ### Explanation of Incorrect Options (Sites of Constriction): There are three primary sites of ureteric constriction: * **A. Ureteropelvic Junction (UPJ):** The first constriction occurs where the wide renal pelvis tapers into the narrow ureter. * **C. Crossing of Iliac Artery:** The second constriction occurs where the ureter crosses the pelvic brim, specifically over the bifurcation of the **common iliac artery** (or the start of the external iliac artery). * **B. Ureterovesical Junction (UVJ):** The third and **narrowest** part of the entire ureter is its intramural passage through the muscular wall of the urinary bladder [1]. ### NEET-PG High-Yield Clinical Pearls: * **Narrowest Point:** The Ureterovesical junction (UVJ) is the most common site for stone impaction. * **Blood Supply:** The ureter receives a segmental blood supply. In the abdomen, the supply comes from the **medial** side (renal, gonadal arteries), while in the pelvis, it comes from the **lateral** side (internal iliac branches) [1]. This is crucial for surgeons to avoid devascularization. * **Water Under the Bridge:** In females, the ureter passes **posterior/inferior** to the uterine artery. * **Pain Referral:** Ureteric colic typically radiates from "loin to groin" (T11–L2 dermatomes).

Question 534: Where are Meissner's plexuses located?

A. Mucosa
B. Submucosa (Correct Answer)
C. Muscularis layer
D. Serosa

Explanation: **Explanation:** The Enteric Nervous System (ENS) is composed of two primary plexuses that coordinate the gastrointestinal tract's functions. **1. Why Submucosa is correct:** **Meissner’s plexus** (also known as the **Submucosal plexus**) is located specifically within the **submucosa** of the intestinal wall [3]. Its primary physiological role is to regulate local secretions (mucus and enzymes), absorption, and local blood flow. It is most prominent in the small and large intestines but is sparse or absent in the esophagus and stomach. **2. Why other options are incorrect:** * **Mucosa:** While the mucosa contains sensory nerve endings [1], it does not house the organized ganglionated plexus known as Meissner’s. * **Muscularis layer:** This layer contains the **Auerbach’s plexus** (Myenteric plexus), located between the inner circular and outer longitudinal muscle layers [2], [3]. Auerbach’s plexus primarily regulates GI motility (peristalsis) [2]. * **Serosa:** This is the outermost epithelial layer and does not contain an intrinsic nervous plexus. **Clinical Pearls & High-Yield Facts for NEET-PG:** * **Origin:** Both Meissner’s and Auerbach’s plexuses are derived from **Neural Crest Cells**. * **Hirschsprung Disease:** This condition results from the failure of neural crest cells to migrate, leading to a **congenital absence** of both Meissner’s and Auerbach’s plexuses in the distal colon (aganglionic segment), causing severe constipation and megacolon. * **Mnemonic:** **M**eissner’s = **M**ucosal secretions/Submucosa; **A**uerbach’s = **A**ction (Motility)/Between muscle layers.

Question 535: While exposing the kidney from behind, which of the following nerves is least likely to be injured?

A. Lateral cutaneous nerve of the thigh (Correct Answer)
B. Ilioinguinal nerve
C. Subcostal nerve
D. Iliohypogastric nerve

Explanation: To understand the risk of nerve injury during a posterior approach to the kidney (such as in a nephrectomy or percutaneous nephrostomy), one must visualize the relationship between the kidney and the posterior abdominal wall muscles. [1] ### **Explanation of the Correct Answer** The kidneys lie on the posterior abdominal wall, specifically resting on the **psoas major, quadratus lumborum, and transversus abdominis** muscles. [2] Several nerves emerge from the lumbar plexus and travel across these muscles, placing them at risk during surgical exposure: * **Subcostal nerve (T12):** Runs inferior to the 12th rib. * **Iliohypogastric and Ilioinguinal nerves (L1):** Emerge from the lateral border of the psoas major and cross the quadratus lumborum, situated directly behind the lower pole of the kidney. The **Lateral cutaneous nerve of the thigh (L2, L3)** also emerges from the lateral border of the psoas major, but it does so much lower in the posterior abdominal wall. It runs across the iliacus muscle toward the anterior superior iliac spine (ASIS). Because it is located significantly **inferior to the kidney**, it is the least likely to be encountered or injured during renal surgery. ### **Analysis of Incorrect Options** * **Subcostal nerve (T12):** This is the most superiorly placed nerve and is frequently encountered during the initial incision in a posterior approach. [2] * **Iliohypogastric & Ilioinguinal nerves (L1):** These nerves lie in the immediate posterior relation to the lower part of the kidney. Retraction or incision in the lumbar region often puts these at high risk. ### **NEET-PG High-Yield Pearls** * **Posterior Relations of Kidney:** Diaphragm (superiorly), Psoas major, Quadratus lumborum, and Transversus abdominis (medial to lateral). * **Order of Nerves (Superior to Inferior):** Subcostal → Iliohypogastric → Ilioinguinal. * **Clinical Sign:** Injury to the iliohypogastric or ilioinguinal nerves during kidney surgery can lead to postoperative sensory loss in the suprapubic region or groin, and potentially a "bulge" in the abdominal wall due to muscle weakness.

Question 536: Surgical lobes of the liver are divided on the basis of which of the following structures?

A. Bile ducts
B. Hepatic veins and portal vein (Correct Answer)
C. Hepatic artery and hepatic vein
D. Hepatic artery and bile ducts

Explanation: The surgical (functional) division of the liver is based on the **Couinaud classification**, which divides the liver into eight independent segments [1]. This division is fundamentally determined by the distribution of the **portal triad** (portal vein, hepatic artery, and bile duct) and the drainage of the **hepatic veins** [1]. 1. **Why Option B is correct:** The liver is divided into right and left surgical lobes by **Cantlie’s line**, an imaginary plane passing from the gallbladder fossa to the IVC. This plane contains the **Middle Hepatic Vein**. Each surgical lobe has its own independent blood supply (from the **Portal Vein** and Hepatic Artery) and biliary drainage [1]. In surgical practice, the hepatic veins act as longitudinal boundaries (intersegmental), while the portal vein branches define the center of the segments (intrasegmental) [1]. 2. **Why other options are incorrect:** * **Options A, C, and D:** While the hepatic artery and bile ducts follow the portal vein branches (forming the portal triad), they are not the primary landmarks used to define the major surgical lobes in isolation. The surgical division specifically relies on the vascular "watershed" areas created by the hepatic veins and the primary bifurcation of the portal vein. **High-Yield Clinical Pearls for NEET-PG:** * **Cantlie’s Line:** Separates the right and left surgical lobes. It is NOT the same as the Falciform ligament (which divides the liver anatomically) [1]. * **Segment IV (Quadrate Lobe):** Belongs to the **Left** surgical lobe but the **Right** anatomical lobe. * **Caudate Lobe (Segment I):** Unique because it receives blood from both right and left portal triads and drains directly into the IVC, bypassing the three main hepatic veins [1]. * **Glisson’s Capsule:** The connective tissue sheath that surrounds the portal triad components as they enter the liver segments.

Question 537: A 50-year-old male, a known case of diverticulosis of the colon, presents with complaints of left lower quadrant pain and bloody stools. He is scheduled for follow-up. The physician begins the workup with an appropriate test of the sigmoid colon by recalling which of its specific features?

A. Is drained by systemic veins
B. Has teniae coli and epiploic appendages (Correct Answer)
C. Receives parasympathetic fibers from the vagus nerve
D. Receives its blood from the superior mesenteric artery

Explanation: ### Explanation **Correct Option: B (Has teniae coli and epiploic appendages)** The sigmoid colon is a part of the large intestine, which is morphologically distinguished from the small intestine by three cardinal features: **teniae coli** (three longitudinal muscle bands), **haustrations** (sacculations), and **omental (epiploic) appendages** (fat-filled peritoneal pouches). In cases of diverticulosis, these features are clinically significant as diverticula typically herniate between the teniae coli where the nutrient vessels (vasa recta) pierce the muscularis propria [1]. **Analysis of Incorrect Options:** * **Option A:** The sigmoid colon is drained by the **sigmoid veins**, which flow into the inferior mesenteric vein (IMV). The IMV joins the splenic vein to form the portal vein; thus, it is drained by the **portal venous system**, not the systemic system. * **Option C:** The sigmoid colon is a **hindgut derivative** [1]. Parasympathetic innervation for the hindgut (from the distal 1/3rd of the transverse colon to the upper anal canal) is supplied by the **pelvic splanchnic nerves (S2–S4)**, not the vagus nerve (which supplies the foregut and midgut). * **Option D:** The blood supply to the sigmoid colon comes from the **sigmoid branches of the Inferior Mesenteric Artery (IMA)**. The Superior Mesenteric Artery (SMA) supplies the midgut structures. **NEET-PG High-Yield Pearls:** * **Diverticulosis Site:** Most common in the **sigmoid colon** due to high intraluminal pressure and smaller diameter. * **Teniae Coli:** These three bands converge at the **base of the appendix**, serving as a surgical landmark for locating it. * **Watershed Areas:** The **splenic flexure (Griffith’s point)** and the **rectosigmoid junction (Sudek’s point)** are highly susceptible to ischemic colitis as they represent the borders of SMA/IMA and IMA/Iliac artery territories respectively.

Question 538: A 43-year-old woman is admitted to the emergency department with esophageal pain and hematemesis after swallowing a fish bone. An endoscopic examination reveals perforation of the intraabdominal portion of the esophageal wall. Which of the following arteries is most likely injured?

A. Branches of left gastric (Correct Answer)
B. Bronchial
C. Thoracic intercostal
D. Branches of right gastric

Explanation: The esophagus is a muscular tube with a segmental blood supply that varies according to its anatomical location. The question specifies a perforation in the **intraabdominal portion** of the esophagus. 1. **Why Option A is Correct:** The intraabdominal esophagus (the distal 2–3 cm) and the cardia of the stomach are primarily supplied by the **esophageal branches of the left gastric artery** (a branch of the celiac trunk) and the **left inferior phrenic artery**. Therefore, a perforation in this specific segment is most likely to injure these vessels. 2. **Why Incorrect Options are Wrong:** * **Option B (Bronchial):** Bronchial arteries supply the **middle third** of the esophagus (thoracic portion) along with direct esophageal branches from the aorta. * **Option C (Thoracic intercostal):** These do not typically provide the primary blood supply to the esophagus; the thoracic portion is supplied by the aorta and bronchial arteries. * **Option D (Branches of right gastric):** The right gastric artery supplies the lesser curvature of the **distal stomach (pylorus)**, not the esophagus. **High-Yield NEET-PG Pearls:** * **Segmental Supply:** * *Cervical:* Inferior thyroid artery. * *Thoracic:* Bronchial arteries and esophageal branches of the Thoracic Aorta. * *Abdominal:* Left gastric artery and Left inferior phrenic artery. * **Venous Drainage:** The abdominal esophagus drains into the **left gastric vein** (portal system). This is a critical site for **porto-systemic anastomosis**; obstruction in the portal vein leads to esophageal varices. * **Constrictions:** The esophagus has four anatomical constrictions; the most common site for foreign body (like a fish bone) entrapment is the first constriction (Cricopharyngeus muscle) [1].

Question 539: Identify the liver segment marked 'F' as per Couinaud's classification?

A. II
B. III
C. IV (Correct Answer)
D. V

Explanation: ***IV*** - Segment IV corresponds to the **left medial segment** or **quadrate lobe**, located between the **middle hepatic vein** and **falciform ligament**. - This segment is anatomically positioned **anterior to the porta hepatis** and is commonly involved in **hepatobiliary surgeries**. *II* - Segment II is the **left lateral superior segment**, located in the **upper portion** of the left lobe above the **left portal vein**. - It lies **lateral to the falciform ligament** and is supplied by the **left hepatic artery** and **left portal vein**. *III* - Segment III is the **left lateral inferior segment**, positioned in the **lower portion** of the left lobe below the **left portal vein**. - This segment is located **lateral to the umbilical fissure** and has distinct vascular supply from the **left hepatic system**. *V* - Segment V is the **right anterior inferior segment**, located in the **lower right portion** of the liver below the **right portal vein**. - It is positioned **medial to the right hepatic vein** and **anterior to the gallbladder fossa**.

Question 540: Which structure is injured while resecting the free edge of the lesser omentum?

A. Cystic duct
B. Portal vein (Correct Answer)
C. Left gastric artery
D. Right gastroepiploic artery

Explanation: The **lesser omentum** is a fold of peritoneum extending from the liver to the lesser curvature of the stomach and the first part of the duodenum [1]. Its free right margin is known as the **hepatoduodenal ligament**, which forms the anterior boundary of the **epiploic foramen (Foramen of Winslow)**. ### Why the Portal Vein is Correct The hepatoduodenal ligament contains the **portal triad**. The anatomical arrangement within this free edge is: * **Anterior-Right:** Common Bile Duct (CBD) * **Anterior-Left:** Hepatic Artery Proper * **Posterior:** **Portal Vein** [2] Because the portal vein lies posteriorly within this bundle, it is at significant risk during surgical maneuvers or resection of the free edge [2]. ### Analysis of Incorrect Options * **Cystic duct (A):** Located within the Calot’s triangle, superior to the duodenum. While it eventually joins the common hepatic duct to form the CBD, it is not considered a primary content of the hepatoduodenal ligament's free edge. * **Left gastric artery (C):** This runs within the **condensed part** of the lesser omentum (hepatogastric ligament) along the lesser curvature of the stomach, not the free edge. * **Right gastroepiploic artery (D):** This travels within the **greater omentum** along the greater curvature of the stomach. ### High-Yield Clinical Pearls for NEET-PG * **Pringle Maneuver:** Surgeons compress the hepatoduodenal ligament (and thus the portal triad) to control bleeding from the liver. * **Epiploic Foramen (Winslow):** The portal vein is anterior to the foramen, while the **Inferior Vena Cava (IVC)** forms its posterior boundary. * **Content Mnemonic:** "D-A-V" (Duct, Artery, Vein) from anterior to posterior.

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Abdomen — MCQs

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