AN55.1-2 | Surface marking — Gate Quiz

Correct! McBurney's point is at the junction of the lateral 1/3 and medial 2/3 of the line joining the right ASIS and the umbilicus — i.e., 1/3 of the way from the ASIS to the umbilicus. This is the surface marking of the appendix base/ileocaecal junction area.

McBurney's point: (1) Line from right ASIS to umbilicus. (2) Go 1/3 of the way from the ASIS. (3) This is the junction of lateral 1/3 and medial 2/3. Clinical use: McBurney's sign (tenderness = appendicitis), Rebound tenderness (Blumberg's sign = peritoneal irritation). McBurney's incision (gridiron incision) is made at 90° to this line for open appendicectomy. Lanz incision = more cosmetic alternative.

Incorrect. McBurney's point = 1/3 from right ASIS toward umbilicus (NOT the midpoint, which would be 1/2 way). The midpoint of the inguinal ligament is the surface marking for the deep inguinal ring and the femoral artery. The point below the pubic tubercle is related to inguinal ring anatomy.

Correct! The inguinal ligament (Poupart's ligament) runs from the anterior superior iliac spine (ASIS) to the pubic tubercle. Its midpoint is therefore halfway between these two structures. The deep inguinal ring lies 1.5 cm above this midpoint.

Inguinal ligament (Poupart's): ASIS → pubic tubercle. Midpoint of inguinal ligament is the key reference for: (1) Deep inguinal ring — 1.5 cm above midpoint. (2) Femoral artery — passes below midpoint (under inguinal ligament). (3) Femoral nerve — lateral to artery (NAVL = nerve, artery, vein, lymphatics from lateral to medial under ligament). (4) Femoral canal — most medial of the three (lymphatics in canal). Note: midpoint of inguinal ligament ≠ mid-inguinal point (which = midpoint between ASIS and pubic symphysis = femoral head location).

Incorrect. The inguinal ligament runs from the ASIS (lateral) to the pubic tubercle (medial — the bony prominence at the medial end of the inguinal crease). NOT to the pubic symphysis (midline). The midpoint of the ASIS-to-pubic-tubercle line = midpoint of inguinal ligament.

Correct! Murphy's sign is elicited by pressing gently at Murphy's point (the right costal margin in the midclavicular line — the surface marking of the gall bladder fundus) and asking the patient to take a deep breath. As the diaphragm descends, the inflamed gall bladder descends to meet the examining fingers, causing pain and inspiratory arrest. A positive Murphy's sign indicates acute cholecystitis.

Murphy's sign: (1) Examiner places hook of right index finger below the right costal margin in the MCL. (2) Asks patient to take a deep breath. (3) Positive = pain and involuntary inspiratory arrest as inflamed gall bladder hits the fingers. (4) Specific for acute cholecystitis. Distinguish: Murphy's POINT (anatomical surface marking of gall bladder) vs Murphy's SIGN (clinical test for cholecystitis) vs Murphy's KIDNEY PUNCH (percussion of costovertebral angle for renal pathology).

Incorrect. Rebound tenderness in the RIF = Blumberg's sign (appendicitis). Costovertebral angle percussion tenderness = renal pathology (pyelonephritis, stone). Pressing left iliac fossa to elicit right iliac fossa pain = Rovsing's sign (appendicitis). Murphy's sign = gallbladder tenderness at the right costal margin/MCL on deep inspiration.

Correct! The spleen projects onto the 9th, 10th, and 11th ribs in the left posterior axillary line. The long axis of the spleen corresponds to the 10th rib. It lies deep to these ribs in the left hypochondrium, covered by the diaphragm.

Spleen surface projection: 9th–11th ribs, left posterior axillary line. Long axis = 10th rib. Lies in the left hypochondrium, between the diaphragm (above) and left colic flexure (below). Not normally palpable. The splenic notch is on the medial border (superior) — differentiates from a left renal mass on examination. Splenomegaly direction: grows toward right iliac fossa following the 10th rib axis.

Incorrect. Spleen = 9th, 10th, 11th ribs (left posterior axillary line). Remember: "1 × 1 × 3 × 9 × 11" — normal spleen is 1 inch thick, 3 inches wide, 5 inches long (1×3×5 in = 2.5×7.5×12.5 cm), weighs 7 oz; surface projection 9th–11th ribs.

Correct! In a healthy adult, the liver extends from the 5th rib (upper border, right MCL) down to the right costal margin (lower border, right MCL). The liver is normally just palpable at the right costal margin on deep inspiration or not palpable at all. Hepatomegaly is defined as the lower border being >2 cm below the costal margin.

Liver surface markings: Right lobe — upper border at 5th rib (right MCL) → lower border at right costal margin. The liver fills RUQ. Left lobe — extends to the left MCL (epigastric region). Total liver percussion span in right MCL = 6–12 cm. Below the costal margin: normally not palpable (or just palpable on deep inspiration in thin individuals). Causes of hepatomegaly: viral hepatitis, cirrhosis (early), congestive heart failure, hepatocellular carcinoma, metastases, haematological malignancies.

Incorrect. The liver upper border is at the 5th rib (right MCL). The lower border is at the right costal margin (right MCL). The umbilicus would indicate massive hepatomegaly. The 2nd intercostal space is far above the liver. The right anterior axillary line at 8th rib describes the most lateral extent of the liver.

Correct! The costovertebral (renal) angle is formed between the 12th rib and the lateral border of the erector spinae (sacrospinalis) muscle. The lower pole of the kidney lies deep to this angle. Tenderness on firm percussion here (kidney punch) indicates renal pathology — pyelonephritis, perinephric abscess, or renal colic (PUJ stone).

Renal angle (costovertebral angle, CVA): formed by the 12th rib (superior) and the lateral border of the erector spinae muscle (medial). The lower pole of the kidney lies deep to this triangle. Clinical examination: firm percussion (kidney punch/Giordano's sign) — tenderness indicates: (1) acute pyelonephritis, (2) perinephric abscess, (3) renal colic (stone at PUJ), (4) acute renal infarction. Note: the 12th rib may be very short in some individuals, making the angle difficult to define.

Incorrect. The renal angle = 12th rib + lateral border of erector spinae. Not the 11th rib, not latissimus dorsi, not the iliac crest. The 12th rib is specifically used because it is the lowest rib and provides direct access over the lower renal pole.

Correct! When the gall bladder is EMPTY, its fundus retracts under the liver and is NOT reliably at the transpyloric plane. The fundus only reaches the transpyloric plane / Murphy's point when the gall bladder is distended. The other structures — pylorus, left kidney hilum, SMA origin — are all reliable L1 transpyloric plane landmarks.

Transpyloric plane (Addison's plane, L1): halfway between jugular notch and pubic symphysis. Fixed landmarks: pylorus (L1, 2.5 cm right of midline), SMA origin (from aorta at L1), left kidney hilum (L1, right kidney L1–L2), neck of pancreas (overlying portal vein formation), duodenojejunal flexure (L2 junction). The fundus of gall bladder is classically stated as a landmark but is unreliable when empty — clinically located at Murphy's point (right MCL × costal margin).

Incorrect. Transpyloric plane (L1) reliable landmarks: pylorus, neck of pancreas, SMA origin, hilum of left kidney, duodenojejunal flexure, 9th costal cartilage tips, conus medullaris (L1–L2). The fundus of the gall bladder is a VARIABLE landmark — it may or may not be at L1 depending on whether the gall bladder is distended or empty.

Correct! The root of the mesentery is approximately 15 cm long and runs obliquely from the duodenojejunal (DJ) flexure — at the level of L2, slightly to the left of the midline — downward and to the right to the right sacroiliac joint. This oblique line is the posterior attachment of the fan-shaped mesentery suspending the small intestine.

Mesentery root (15 cm): DJ flexure (L2, 2.5 cm left of midline) → right sacroiliac joint. It crosses: 3rd part of duodenum, aorta, IVC, right ureter, right gonadal vessels, psoas major. The root divides the right paracolic gutter from the mesenteric region of the abdomen. Clinically: the mesenteric root is important in small bowel volvulus (twists around this root), Crohn's disease (thickening of mesentery), and surgical bowel mobilisation.

Incorrect. The root of mesentery: DJ flexure (L2, left of midline) → right sacroiliac joint. This 15 cm root supports the entire small bowel mesentery (~6 m of small intestine). It is NOT between the hepatic and splenic flexures (those are colonic flexures). The pylorus to ileocaecal junction is a loose description of the small bowel itself.

Correct! Courvoisier's law: a palpable, non-tender, distended gall bladder in the presence of jaundice is unlikely to be due to gallstones. Gallstones cause repeated inflammation → fibrosis → shrunken, thickened, non-distensible gall bladder. The palpable, non-tender GB with obstructive jaundice = malignant obstruction distal to the cystic duct entry point (usually carcinoma of the head of pancreas, cholangiocarcinoma, or periampullary carcinoma).

Courvoisier's law (1890): "In a jaundiced patient, if the gall bladder is palpable, the jaundice is unlikely to be due to gallstones." Because: gallstones cause chronic cholecystitis → fibrosis → shrunken contracted gall bladder unable to distend. Palpable + non-tender GB + progressive jaundice = malignant obstruction of CBD (head of pancreas carcinoma most common). Exceptions: mucocele of gall bladder (late-stage distension from stone), double-stone obstruction. Courvoisier's sign = palpable non-tender distended GB. Murphy's sign = tender GB on inspiration (cholecystitis).

Incorrect. Courvoisier's law specifically states that a palpable non-tender distended GB + jaundice is NOT due to gallstones (which cause a fibrosed, shrunken GB). Acute cholecystitis would cause a tender GB + fever. Viral hepatitis causes intrahepatic jaundice, not a distended GB. Empyema of GB from stones would be tender.

Correct! The caecum and appendix are located in the right iliac fossa (right inguinal region) — the lower right region of the nine-region division. This is why appendicitis typically presents with pain in the right iliac fossa, maximal at McBurney's point.

Nine regions and their contents: Epigastric — stomach, liver (left lobe), duodenum (1st part), pancreas (head), transverse colon. Right hypochondrium — liver (right lobe), gall bladder, hepatic flexure. Left hypochondrium — stomach (fundus), spleen, splenic flexure. Right lumbar — ascending colon, right kidney (lower pole). Umbilical — small intestine, transverse colon, omentum. Left lumbar — descending colon, left kidney. Right iliac fossa — caecum, appendix, terminal ileum. Hypogastric — bladder, uterus, sigmoid, rectum. Left iliac fossa — sigmoid colon.

Incorrect. The right iliac fossa is the correct region for the caecum and appendix. Right lumbar = ascending colon + part of right kidney. Hypogastric = urinary bladder, uterus, sigmoid colon, rectum (upper). Epigastric = stomach, liver (left lobe), pancreas head, duodenum.