Abdomen — MCQs

Abdomen Indian Medical PG Practice Questions and MCQs

Question 211: The midgut is supplied by which artery?

A. Renal Artery
B. Celiac Trunk
C. Arch of Aorta
D. Superior mesenteric artery (Correct Answer)

Explanation: The blood supply to the gastrointestinal tract is organized embryologically based on the division of the primitive gut tube. **Correct Answer: D. Superior Mesenteric Artery (SMA)** The **Superior Mesenteric Artery** is the artery of the **midgut** [1]. The midgut extends from the second part of the duodenum (distal to the opening of the common bile duct) to the junction of the proximal two-thirds and distal one-third of the transverse colon [1], [2]. The SMA arises from the abdominal aorta at the level of the L1 vertebra. **Explanation of Incorrect Options:** * **A. Renal Artery:** These are paired lateral branches of the aorta (L1-L2 level) that supply the kidneys and adrenal glands; they do not supply the gut tube. * **B. Celiac Trunk:** This is the artery of the **foregut** [2]. It supplies structures from the lower esophagus to the second part of the duodenum, as well as the liver, pancreas, and spleen. * **C. Arch of Aorta:** This is located in the superior mediastinum and gives off branches (Brachiocephalic, Left Common Carotid, Left Subclavian) to supply the head, neck, and upper limbs. **High-Yield Clinical Pearls for NEET-PG:** 1. **The Rule of Three:** * Foregut $\rightarrow$ Celiac Trunk (T12) * Midgut $\rightarrow$ Superior Mesenteric Artery (L1) * Hindgut $\rightarrow$ Inferior Mesenteric Artery (L3) 2. **SMA Syndrome:** Compression of the third part of the duodenum between the SMA and the Aorta [2]. 3. **Midgut Volvulus:** Often involves a "whirlpool sign" on imaging, caused by the twisting of the midgut around the SMA axis. 4. **Watershed Area:** The **Griffith’s point** (splenic flexure) is a high-yield site for ischemic colitis where the territories of the SMA and IMA meet [1].

Question 212: Which of the following is true about the Houston's valves?

A. They disappear on distension.
B. They contain all layers of the muscularis.
C. They are placed transversely. (Correct Answer)
D. The middle valve is the most constant and folds towards the right side.

Explanation: **Houston’s valves** (also known as Plicae Circulares of the rectum) are permanent, crescentic mucosal folds found within the rectum. [1] ### **Explanation of the Correct Answer** **Option C is correct** because Houston’s valves are **transverse (horizontal) folds** that project into the rectal lumen. They are typically three in number: superior, middle, and inferior. Their primary function is to support the weight of fecal matter and prevent it from pressing directly on the anal sphincters, thereby assisting in fecal continence. ### **Analysis of Incorrect Options** * **Option A:** Unlike the longitudinal folds of the stomach or the temporary folds of the empty rectum, Houston’s valves are **permanent**. They do **not disappear** when the rectum is distended with feces or air. * **Option B:** These valves are formed by the mucosa, submucosa, and the **circular muscle layer** only. They do not contain the longitudinal muscle layer (which forms the outer coat of the rectum). * **Option C:** The **middle valve (Kohlrausch’s fold)** is indeed the most constant and largest, but it projects from the **left wall** and folds towards the **right side** (Wait, correction for clarity: It is situated on the **right side** of the rectum, approximately 7-8 cm from the anus). *Note: Standard anatomy texts state the middle valve is on the right, while the superior and inferior are on the left.* ### **NEET-PG High-Yield Pearls** * **Location:** The middle valve (Kohlrausch’s fold) corresponds to the level of the **rectovesical pouch** in males and the **rectouterine pouch (Douglas)** in females. * **Clinical Significance:** These valves can act as obstructions during sigmoidoscopy or colonoscopy; the scope must be maneuvered around them. * **Level:** The rectum begins at the level of **S3** and ends at the anorectal junction. It lacks haustrations, teniae coli, and appendices epiploicae. [1]

Question 213: Valvulae conniventes are seen in which part of the small intestine?

A. Jejunum (Correct Answer)
B. Ileum
C. Stomach
D. Colon

Explanation: **Explanation:** **Valvulae conniventes** (also known as Plicae circulares or Valves of Kerckring) are large, permanent circular folds of the mucous membrane found in the small intestine. They begin in the second part of the duodenum and are **most numerous, tallest, and most developed in the Jejunum**. Their primary function is to increase the surface area for absorption and slow down the passage of chime. * **Jejunum (Correct):** It is characterized by thick walls and a "feathery" appearance on barium studies due to the high density of tall, closely packed valvulae conniventes [2]. * **Ileum (Incorrect):** While present in the proximal ileum, they become smaller, fewer, and eventually disappear in the distal part of the ileum [3]. The ileum is smoother and thinner compared to the jejunum. * **Stomach (Incorrect):** The stomach contains longitudinal folds called **Rugae**, which flatten out when the stomach is distended. * **Colon (Incorrect):** The large intestine is characterized by **Haustrations** (sacculations) produced by the tonicity of the Taenia coli, and internal folds called semilunar folds, but it lacks valvulae conniventes [1]. **Clinical Pearls for NEET-PG:** 1. **Radiological Sign:** On a plain X-ray of the abdomen, the valvulae conniventes cross the **entire width** of the bowel loop (Coiled spring appearance), helping to distinguish small bowel obstruction from large bowel obstruction (where Haustra only partially cross the lumen). 2. **Absorption:** The presence of these folds increases the intestinal surface area by approximately **3-fold** [1]. 3. **Histology:** Unlike rugae in the stomach, valvulae conniventes are permanent and do not disappear when the intestine is distended [2].

Question 214: What anatomical structure forms the superior border of the epiploic foramen?

A. Caudate lobe of liver (Correct Answer)
B. Hepatic artery
C. Bile duct
D. Inferior vena cava

Explanation: The **Epiploic Foramen** (also known as the Foramen of Winslow) is a critical anatomical communication between the Greater Sac and the Lesser Sac (Omental Bursa). Understanding its boundaries is a high-yield topic for NEET-PG. ### **Anatomical Boundaries** The superior border is formed by the **Caudate Lobe of the Liver** (specifically the caudate process) [1]. This structure forms the "roof" of the opening. ### **Why the other options are incorrect:** * **B & C (Hepatic Artery and Bile Duct):** These structures, along with the Portal Vein, are contained within the free edge of the **Lesser Omentum** (hepatoduodenal ligament). This complex forms the **Anterior** border of the foramen, not the superior. * **D (Inferior Vena Cava):** The IVC, covered by parietal peritoneum, forms the **Posterior** border of the foramen [1]. ### **Summary of Boundaries (High-Yield):** * **Superior:** Caudate lobe of the liver. * **Inferior:** First part of the Duodenum and the horizontal part of the hepatic artery. * **Anterior:** Free margin of the Lesser Omentum (containing the Portal triad: Bile duct, Hepatic artery, and Portal vein). * **Posterior:** Inferior Vena Cava (IVC) and the right crus of the diaphragm [1]. ### **Clinical Pearl: Pringle’s Maneuver** In cases of severe liver trauma or hemorrhage, a surgeon can compress the structures in the **anterior border** of the epiploic foramen (the hepatoduodenal ligament) to control bleeding. This is known as **Pringle’s Maneuver**. If bleeding continues despite this, the source is likely the IVC (posterior border) or hepatic veins.

Question 215: Which organ is supplied by the portal vein?

A. Spleen
B. Liver (Correct Answer)
C. Pancreas
D. Colon

Explanation: ### Explanation **Correct Answer: B. Liver** **The Underlying Concept:** The portal vein is a unique vessel that forms part of a **portal venous system**, which begins in one capillary bed and ends in another [2]. It is formed by the union of the **Superior Mesenteric Vein (SMV)** and the **Splenic Vein** behind the neck of the pancreas [1]. Unlike most veins that carry blood toward the heart, the portal vein carries nutrient-rich, deoxygenated blood from the gastrointestinal tract and associated organs directly **to the liver** [2]. The liver receives approximately 75% of its blood supply from the portal vein and 25% from the hepatic artery [1], [3]. **Why the other options are incorrect:** * **A. Spleen:** The spleen is a "tributary" organ. It is drained by the splenic vein, which then contributes to the formation of the portal vein. It is supplied by the **Splenic Artery**. * **C. Pancreas:** The pancreas is supplied by branches of the **Celiac Trunk** and **Superior Mesenteric Artery** (e.g., pancreaticoduodenal arteries) [2]. Its venous drainage flows into the portal system, but it is not supplied by it. * **D. Colon:** The colon is supplied by the **Superior and Inferior Mesenteric Arteries**. Like the rest of the gut, its venous blood drains into the portal vein to be processed by the liver [2]. **NEET-PG High-Yield Pearls:** * **Site of Formation:** At the level of the **L2 vertebra**, behind the neck of the pancreas [1]. * **Portal-Systemic Anastomoses:** Important clinical sites where the portal and systemic circulations meet include the lower esophagus (esophageal varices), umbilicus (caput medusae), and rectum (hemorrhoids). * **Portal Triad:** The portal vein enters the liver through the porta hepatis as part of the portal triad, alongside the hepatic artery and the common bile duct [3]. * **Valveless Nature:** The portal vein and its tributaries have no valves, which allows for the backflow of blood in portal hypertension [1].

Question 216: Short gastric arteries are branches of which artery?

A. Celiac artery
B. Splenic artery (Correct Answer)
C. Left gastroepiploic artery
D. Left gastroepiploic artery

Explanation: **Explanation:** The **short gastric arteries** (usually 5–7 in number) arise from the **splenic artery** [1] or its terminal branches. They reach the stomach by passing through the **gastrosplenic ligament** to supply the fundus of the stomach. **Why the Splenic Artery is correct:** The splenic artery is one of the three main branches of the celiac trunk. As it approaches the hilum of the spleen, it gives off the short gastric arteries [1] and the left gastroepiploic artery. These vessels form a critical part of the stomach's rich collateral blood supply. **Analysis of Incorrect Options:** * **Celiac Artery:** While the splenic artery originates from the celiac trunk [1], the short gastric arteries are distal branches of the splenic artery itself, not direct branches of the celiac trunk. * **Left Gastroepiploic Artery:** This is also a branch of the splenic artery. It runs along the greater curvature of the stomach. While it shares an origin with the short gastric arteries, it is a distinct vessel. **High-Yield Clinical Pearls for NEET-PG:** 1. **Vulnerability in Splenectomy:** During a splenectomy, if the gastrosplenic ligament is not handled carefully, the short gastric arteries can be damaged, leading to potential ischemia of the gastric fundus. 2. **Gastric Varices:** In cases of **splenic vein thrombosis** (often due to chronic pancreatitis), blood is diverted through the short gastric veins into the gastric submucosa to reach the portal system, leading to isolated gastric varices in the fundus. 3. **Watershed Area:** The fundus is a "watershed" zone; since short gastric arteries do not anastomose as robustly as other gastric vessels, it is more susceptible to ischemic injury if the splenic artery is occluded proximally.

Question 217: Which of the following statements is NOT true concerning the dentate line of the anal canal?

A. It is the mucocutaneous junction joining the embryonic hindgut and the proctodeum.
B. The columnar epithelium of the rectum is replaced at the level of the dentate line.
C. The anal canal below the dentate line contains the columns of Morgagni. (Correct Answer)
D. Distal to the dentate line, the anus is lined with stratified squamous epithelium.

Explanation: ### Explanation The **dentate (pectinate) line** is a critical anatomical landmark in the anal canal, representing the site of fusion between the endodermal hindgut and the ectodermal proctodeum. [2] **Why Option C is the correct (NOT true) statement:** The **anal columns (Columns of Morgagni)** are longitudinal mucosal folds located in the **upper half** of the anal canal, which is **above (proximal to)** the dentate line. These columns end inferiorly at the anal valves, which collectively form the dentate line. [1] Therefore, stating they are below the line is anatomically incorrect. **Analysis of other options:** * **Option A:** This is true. The dentate line marks the embryological transition where the endoderm (hindgut) meets the invaginating ectoderm (proctodeum). [2] * **Option B:** This is true. Above the dentate line, the mucosa is lined by simple columnar epithelium (similar to the rectum), which transitions into a transitional zone (anal transition zone) at the level of the line. * **Option D:** This is true. Distal to the dentate line, the lining becomes non-keratinized stratified squamous epithelium, which eventually becomes keratinized skin at the anal verge. ### High-Yield Clinical Pearls for NEET-PG: * **Nerve Supply:** Above the line is autonomic (painless internal hemorrhoids); below the line is somatic via the inferior rectal nerve (painful external hemorrhoids). * **Lymphatic Drainage:** Above the line drains to **Internal Iliac nodes**; below the line drains to **Superficial Inguinal nodes**. * **Venous Drainage:** Above the line drains to the Portal system (Superior Rectal vein); below the line drains to the Systemic system (Inferior Rectal vein). [3] This is a key site for **Porto-systemic anastomosis**. * **Development:** Above = Endoderm; Below = Ectoderm. [2]

Question 218: The mesentery of the small intestine, along its attachment to the posterior abdominal wall, crosses all of the following structures except?

A. Left gonadal vessels (Correct Answer)
B. Third part of the duodenum
C. Abdominal aorta
D. Right ureter

Explanation: ### Explanation The **root of the mesentery** is a 15 cm long, oblique border that attaches the small intestine to the posterior abdominal wall. It extends from the **duodenojejunal flexure** (left side of L2 vertebra) to the **ileocaecal junction** (right sacroiliac joint). **Why Option A is Correct:** The root of the mesentery travels obliquely from **upper-left to lower-right**. Because it begins at the midline/left of the L2 vertebra and moves immediately toward the right side, it **never crosses the left gonadal vessels** or the left ureter. These structures lie lateral to the point of origin and remain on the left side of the posterior abdominal wall. **Why the Other Options are Incorrect:** As the root descends across the posterior abdominal wall, it sequentially crosses the following structures from left to right: * **Abdominal Aorta (Option C):** Crossed at its origin near the L2 level. * **Inferior Vena Cava (IVC):** Crossed as it moves toward the right. * **Third part of the Duodenum (Option B):** The root passes directly over the horizontal part of the duodenum [1]. * **Right Psoas Major:** The muscle on which the root rests. * **Right Ureter (Option D):** Crossed as it approaches the right iliac fossa. * **Right Gonadal Vessels:** Crossed just before reaching the ileocaecal junction. **High-Yield Clinical Pearls for NEET-PG:** * **Length Comparison:** The root is only 15 cm (6 inches) long, whereas the intestinal border is approximately 6 meters long, allowing for the characteristic folding of the small bowel. * **Contents:** The mesentery contains the superior mesenteric artery and vein, lymph nodes, fat, and autonomic nerves. * **Surgical Note:** During surgery, the root of the mesentery serves as a landmark; the **Superior Mesenteric Artery** enters the root anterior to the third part of the duodenum [1].

Question 219: During surgical treatment of portal hypertension in a 59-year-old man with liver cirrhosis, a surgeon inadvertently lacerates the dilated paraumbilical veins. The veins must be repaired to allow collateral flow. Which of the following ligaments is most likely severed?

A. Splenorenal ligament
B. Gastrosplenic ligament
C. Gastrophrenic ligament
D. Ligamentum teres hepatis (Correct Answer)

Explanation: The **paraumbilical veins** are small vessels that run within the **ligamentum teres hepatis** (the obliterated umbilical vein) [1]. In patients with portal hypertension (often due to liver cirrhosis), these veins undergo compensatory dilation to shunt blood from the portal system (left branch of the portal vein) to the systemic system (superficial epigastric veins). This portosystemic anastomosis manifests clinically as **Caput Medusae**. Therefore, any surgical procedure involving the repair or accidental laceration of these dilated veins directly involves the ligamentum teres. **2. Why Other Options are Incorrect:** * **Splenorenal Ligament:** Connects the left kidney to the spleen. It contains the splenic artery, splenic vein, and the tail of the pancreas [2]. It does not house paraumbilical veins. In portal hypertension, surgical splenorenal shunts can be performed to divert portal flow to the systemic renal vein [3]. * **Gastrosplenic Ligament:** Connects the greater curvature of the stomach to the spleen. It contains the short gastric and left gastro-omental vessels [2]. * **Gastrophrenic Ligament:** Connects the superior part of the stomach to the diaphragm. It does not contain major portosystemic collateral vessels. **3. NEET-PG High-Yield Pearls:** * **Ligamentum Teres Hepatis:** Remnant of the **Left Umbilical Vein** [1]. It is found in the free margin of the **falciform ligament** [1]. * **Ligamentum Venosum:** Remnant of the **Ductus Venosus**. * **Portosystemic Anastomosis Sites:** 1. **Lower Esophagus:** Left gastric vein (Portal) + Azygos vein (Systemic) → Esophageal varices. 2. **Umbilicus:** Paraumbilical veins (Portal) + Superficial epigastric veins (Systemic) → Caput Medusae. 3. **Rectum:** Superior rectal vein (Portal) + Middle/Inferior rectal veins (Systemic) → Anorectal varices (Internal hemorrhoids).

Question 220: Occlusion to the superior mesenteric artery affects which part of the gastrointestinal tract?

A. Pyloric antrum
B. Fundus of stomach
C. Duodenum distal to the opening of the common bile duct (Correct Answer)
D. Greater curvature of the stomach

Explanation: ### Explanation The **Superior Mesenteric Artery (SMA)** is the artery of the **midgut** [1]. To answer this question, one must understand the embryological divisions of the gastrointestinal tract and their respective blood supplies: 1. **Foregut:** Esophagus to the 2nd part of the duodenum (at the opening of the common bile duct). Supplied by the **Celiac Trunk** [2]. 2. **Midgut:** Distal 2nd part of the duodenum to the junction of the proximal 2/3 and distal 1/3 of the transverse colon. Supplied by the **SMA** [1]. 3. **Hindgut:** Distal 1/3 of the transverse colon to the upper part of the anal canal. Supplied by the **Inferior Mesenteric Artery (IMA)** [1]. **Why Option C is Correct:** The transition from foregut to midgut occurs at the **Major Duodenal Papilla** (where the common bile duct opens). Therefore, the duodenum distal to this point is midgut territory and is primarily supplied by the **inferior pancreaticoduodenal artery**, a branch of the SMA [2]. **Why Other Options are Incorrect:** * **Options A, B, and D:** The pyloric antrum, fundus, and greater curvature are all parts of the **stomach**. The stomach is a foregut structure entirely supplied by branches of the **Celiac Trunk** (Left/Right Gastrics, Left/Right Gastro-epiploics, and Short Gastric arteries). ### High-Yield NEET-PG Pearls: * **SMA Syndrome:** Compression of the 3rd part of the duodenum between the SMA and the Abdominal Aorta, often seen after rapid weight loss. * **Nutcracker Syndrome:** Compression of the Left Renal Vein between the SMA and the Aorta. * **Watershed Areas:** The **Splenic Flexure (Griffith’s point)** is a common site for ischemic colitis as it is the territory where SMA and IMA supply meet [1]. * **Midgut structures supplied by SMA:** Lower half of duodenum, jejunum, ileum, cecum, appendix, ascending colon, and proximal 2/3 of transverse colon [2].

Practice by Chapter

Anterior Abdominal Wall

Practice Questions

Peritoneum and Peritoneal Cavity

Practice Questions

Stomach and Intestines

Practice Questions

Liver, Gallbladder and Biliary Tract

Practice Questions

Pancreas and Spleen

Practice Questions

Kidneys and Suprarenal Glands

Practice Questions

Abdominal Vasculature

Practice Questions

Posterior Abdominal Wall

Practice Questions

Innervation of Abdominal Viscera

Practice Questions

Applied Anatomy and Clinical Correlations

Practice Questions

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free

Abdomen — MCQs

Abdomen — MCQs

On this page

Practice by Chapter

Want unlimited practice?