FREEMEDSITE MRCS ACADEMY • ARTICLE 15 • PAPER 1 SURGICAL ANATOMY

Thoracic, Pelvic and Visceral Surgical Anatomy Made Easy for MRCS Part A

Learn high-yield relationships of the chest wall, mediastinum, great vessels, ureter, pudendal nerve, peritoneal sacs, liver, pancreas and bowel. Apply the anatomy in 40 original five-option clinical SBAs.

12 teaching modules52 saved revision topics40 explained A–E SBAs3 original schematic diagrams

FreeMedSite educational article • 16 October 2026 • Independent original practice questions, not official exam papers

How to study this chapter

Read one anatomical region, then identify three things: what is at risk during surgery, how to recognise its injury, and which easily confused structures are nearby. Tick the revision objectives and attempt original MRCS-style five-option questions. Every option has its own rationale.

Recall provenance: Your uploaded MRCS recalls were used to identify commonly tested concepts (e.g. pleural nerve supply, the ureter, lesser sac, and pancreatic vessels). Recalled answer keys were not treated as verified. These are new educational questions.

Study resource only; use current clinical protocols and specialist guidance for procedures or emergency cases.

On this page

Thoracic wall, ribsMediastinum, pleuraHeart, great vesselsDiaphragm, oesophageal hiatusPelvic brim, ureterPelvic floor, perineumRectum, anal canalPeritoneal sacs, lesser sacStomach, splenic vesselsPortal triad, cystohepatic trianglePancreas, duodenumMidgut, appendix, colon52-topic checklist40 SBAsFAQsReferences and lessons

1. Thoracic wall, ribs and pleural anatomy

The main intercostal vein, artery and nerve travel together in the costal groove along the inferior border of each rib, usually arranged superior-to-inferior as VAN. A smaller collateral bundle may run near the upper border of the rib below. Somatic pain from costal pleura is transmitted by intercostal nerves, whereas the central diaphragmatic pleura is supplied by the phrenic nerve.

Applied surgical anatomy

For a chest drain, assess the safe triangle, select an appropriate interspace and insert just superior to the upper border of the lower rib in that interspace to minimise injury to the main bundle. No landmark eliminates the need for safe technique.

MRCS pearl

Do not confuse pain from costal pleura (intercostal nerves) and central diaphragmatic pleura (phrenic nerve).

Main VAN bundle is along the inferior surface of the upper rib. A smaller collateral bundle may also be present.

2. Mediastinum, pleura and oesophageal relationships

The phrenic nerves course anterior to the lung roots and supply the diaphragm. The vagus nerves pass posterior to the roots and contribute to the oesophageal plexus. The thoracic duct ascends in the posterior mediastinum, typically crossing from right to left near the mid-thorax and entering the left venous angle. The recurrent laryngeal nerves differ: right loops below the subclavian artery; left under the aortic arch near the ligamentum arteriosum.

Applied surgical anatomy

During oesophageal or mediastinal surgery, identify vagal, recurrent laryngeal and thoracic duct structures; injury can cause voice dysfunction or chylothorax.

MRCS pearl

Phrenic = anterior to hilum; vagus = posterior. Do not reverse them.

3. Heart, great vessels and coronary circulation

The right ventricle forms much of the anterior sternocostal surface, while the left ventricle contributes the left border and apex. The SA node is commonly supplied by the RCA, but origin varies. The posterior descending artery originates from the dominant coronary system (usually RCA), while the left anterior descending artery runs in the anterior interventricular groove.

Applied surgical anatomy

Anterior penetrating trauma may threaten the right ventricle; coronary dominance is defined by the origin of the posterior descending artery rather than the size of the RCA.

MRCS pearl

Anterior interventricular groove = LAD; posterior interventricular groove = PDA.

4. Diaphragm, oesophageal hiatus and embryology

The caval aperture is at T8, oesophageal hiatus at T10 and aortic hiatus at T12 (approximate vertebral levels). The IVC passes through the central tendon; oesophagus accompanies vagal trunks; aorta passes posterior to the diaphragm with the thoracic duct. The phrenic nerve (C3–C5) supplies motor innervation. Posterolateral Bochdalek hernias result from failed pleuroperitoneal canal closure.

Applied surgical anatomy

Consider congenital diaphragmatic hernia in neonatal respiratory distress, and recognise referred shoulder-tip pain from phrenic afferents.

MRCS pearl

T8 IVC, T10 oesophagus, T12 aorta is a useful anatomical approximation; the aorta is posterior to the diaphragm.

5. Pelvic brim, ureter and pelvic arterial crossings

The ureter enters the pelvis anterior to the iliac-vessel bifurcation or proximal external iliac artery, descends on the lateral pelvic wall, and passes beneath the uterine artery close to the cervix before entering the posterolateral bladder. In men it passes beneath the ductus deferens near the bladder. The distal ureter has important perioperative vulnerability.

Applied surgical anatomy

During hysterectomy, protect the ureter while securing the uterine vessels. The mnemonic water under the bridge describes ureter beneath uterine artery.

MRCS pearl

Ureter under uterine artery; never confuse crossing with the ovarian vessels or vas deferens.

Schematic: “water under the bridge” — the ureter passes beneath the uterine artery close to the cervix.

6. Pelvic floor, perineum and pudendal structures

Levator ani includes puborectalis, pubococcygeus and iliococcygeus. Puborectalis maintains the anorectal angle and supports continence. Pudendal nerve (S2–S4) exits via the greater sciatic foramen below piriformis, wraps around the sacrospinous ligament near the ischial spine and enters the perineum through the lesser sciatic foramen, continuing in Alcock canal.

Applied surgical anatomy

The ischial spine is a landmark for pudendal nerve block. Perineal injury can affect external sphincters and sensory innervation.

MRCS pearl

Pudendal nerve is mainly somatic; pelvic splanchnic parasympathetics are separate S2–S4 pathways.

7. Rectum, anal canal and bladder surgery

Above the pectinate line, anal mucosa has visceral sensory innervation and predominantly internal iliac lymphatic drainage; below it, somatic sensation via inferior rectal nerves and superficial inguinal lymph drainage are important. The bladder trigone is bordered by two ureteric orifices and the internal urethral opening. Its distension changes relationships in the lower abdomen.

Applied surgical anatomy

Choose correct lymph-node basin for distal anal lesions and distinguish the pain of external from internal haemorrhoids.

MRCS pearl

Pectinate line changes innervation, epithelial lining, vessels and lymphatics.

8. Peritoneal sacs, lesser sac and epiploic foramen

The lesser sac is posterior to the stomach and lesser omentum. The epiploic foramen connects greater and lesser sacs. The hepatoduodenal ligament forms its anterior boundary and encloses the portal triad; IVC is posterior, caudate lobe superior and first part of duodenum inferior. The hepatorenal recess is dependent in a supine patient.

Applied surgical anatomy

A Pringle manoeuvre compresses the hepatoduodenal ligament to temporarily control portal inflow, not hepatic vein outflow.

MRCS pearl

Lesser sac lies behind the stomach; foramen anterior boundary = portal triad in hepatoduodenal ligament.

9. Stomach, splenic vessels and foregut supply

The foregut is supplied mainly by the coeliac trunk. The left gastric supplies the lesser curvature, while short gastric arteries arise from the splenic artery and travel in the gastrosplenic ligament to the fundus. The posterior stomach relates to the lesser sac and pancreas. The splenic artery is tortuous and runs along the superior border of the pancreas.

Applied surgical anatomy

In splenic surgery the short gastric vessels may bleed; preservation or division depends on the operation and perfusion plan.

MRCS pearl

Do not confuse short gastric arteries with left gastric artery supplying the lesser curvature.

10. Portal triad, cystohepatic triangle and liver surface

The hepatoduodenal ligament transmits the portal vein posteriorly, common bile duct anterolaterally (right), and proper hepatic artery anteromedially (left). The modern hepatocystic triangle boundaries are cystic duct, common hepatic duct and inferior liver surface; the cystic artery often traverses it but branching patterns vary. The ligamentum teres carries the remnant of the left umbilical vein.

Applied surgical anatomy

Safe cholecystectomy requires the critical view of safety, not reliance on a single presumed textbook course of the cystic artery.

MRCS pearl

Calot terminology can differ historically; state the modern hepatocystic boundaries when answering anatomy.

Typical portal triad orientation: duct anterolateral/right, artery anteromedial/left, portal vein posterior.

11. Pancreas, duodenum and vascular relations

The pancreatic neck lies anterior to the portal vein formation (SMV joining splenic vein). The uncinate process hooks posterior to superior mesenteric vessels. The second part of the duodenum receives the bile and pancreatic ducts at the major duodenal papilla. Superior and inferior pancreaticoduodenal arterial arcades connect coeliac and SMA territories.

Applied surgical anatomy

Pancreaticoduodenectomy requires understanding the SMA/SMV relationships and portal-vein formation behind the pancreatic neck.

MRCS pearl

Uncinate is posterior to mesenteric vessels; portal vein forms posterior to pancreatic neck.

12. Midgut, appendix, colon and retroperitoneal viscera

The SMA supplies midgut from distal duodenum through proximal two-thirds of transverse colon; IMA supplies hindgut. The base of appendix lies where three taeniae coli converge on the caecum. Secondarily retroperitoneal structures include ascending/descending colon and most duodenum, excluding the proximal first part. The ureter lies retroperitoneally on psoas.

Applied surgical anatomy

Locate an appendix base by tracing taeniae coli; identify ureter during colonic mobilisation, and distinguish retroperitoneal organs from intraperitoneal viscera.

MRCS pearl

Colonic watershed at splenic flexure is between SMA and IMA territories; appendix base corresponds to taeniae convergence.

52-topic interactive revision checklist

Tick when you can describe the structure, demonstrate its relation on a labelled sketch and explain an operative complication. Progress saves automatically in this browser under the unique Article 15 key.

0 / 52 topics completed

Saved locally on this browser/device; no automatic cross-device sync. Clearing browser data may remove progress.

Thoracic wall & pleura

Costal groove order VANChest-drain safe triangle and rib positionCostal versus diaphragmatic pleural sensationVisceral versus parietal pleuraIntercostal nerve dermatomal supply

Mediastinum

Phrenic versus vagus relation to lung rootThoracic duct course and drainageLeft versus right recurrent laryngeal loopsAzygos arch and SVC relationshipThoracic oesophageal plexus

Heart & coronary

Anterior cardiac surface and right ventricleCoronary dominance and PDA originLAD territory and courseAtrial chamber bordersPulmonary versus systemic venous return

Diaphragm

T8 T10 T12 major diaphragmatic openingsPhrenic C3–C5 supplyBochdalek hernia embryologyReferred shoulder-tip pain mechanism

Pelvic ureter

Ureter at pelvic brimUterine artery and ureter crossingDuctus deferens crossing over ureterDistal ureter injury during hysterectomy

Pelvic floor

Levator ani componentsPuborectalis anorectal anglePudendal course through foraminaIschial spine and pudendal block

Rectum & bladder

Pectinate line sensationAnal canal lymph drainage above/belowInternal versus external haemorrhoid painRectal blood supply overviewBladder trigone boundaries

Peritoneum

Greater versus lesser sacEpiploic foramen boundariesPringle manoeuvre anatomyHepatorenal recess and supine fluid

Foregut

Coeliac trunk principal branchesShort gastric vessels and gastrosplenic ligamentLesser curvature blood supplyStomach posterior bed and lesser sac

Hepatobiliary

Portal triad orientationHepatocystic triangle boundariesCritical view of safety principlesCystic artery anatomical variations

Pancreas

Portal vein behind pancreatic neckUncinate and mesenteric vesselsMajor duodenal papilla locationPancreaticoduodenal arcade circulation

Midgut & hindgut

SMA and IMA supply boundariesAppendix taenia coli convergenceSecondarily retroperitoneal colonSplenic flexure watershed

40 original MRCS-style clinical SBAs

Each question has five options (A–E), one best answer, an explanation of every option, a useful exam pearl, an examiner trap and an answered viva extension. Positions are balanced evenly across A–E.

Quiz score, marked answers and current question save automatically in your browser.

0 / 40Marked

0Correct

N/AAccuracy

Question 1 of 40

Question 1 of 40 • Chest drain

Q01. A chest drain is inserted into the fifth intercostal space. Which edge of the rib below the selected space is preferred for entry to minimise injury to the principal intercostal bundle?

A. Just superior to its upper borderB. Immediately below the rib aboveC. Through the inferior costal grooveD. Directly through rib cartilageE. Through the middle of the rib cortex

View detailed explanation, examiner trap and viva

Correct answer: A. Just superior to its upper border.

Why correct: The main intercostal vein, artery and nerve course in the costal groove along the lower border of the rib above. Entry over the upper edge of the lower rib reduces the risk of transecting this bundle.

Why the other options are incorrect:

B. Immediately below the rib above: This passes near the main costal-groove bundle.

C. Through the inferior costal groove: The groove contains the main neurovascular bundle.

D. Directly through rib cartilage: Chest drainage requires entry into the correct intercostal space rather than through cartilage.

E. Through the middle of the rib cortex: A rib itself is not a safe soft-tissue pathway into pleura.

Exam pearl: The main bundle is under the upper rib in each interspace.

Examiner trap: Collateral vessels can still exist near the lower rib; positioning does not make blind insertion harmless.

Viva extension — What does VAN denote? Answer: Vein, artery and nerve, superior to inferior in the main groove.

Question 2 of 40 • Parietal pleura

Q02. Local anaesthetic is infiltrated into the lateral costal pleura for chest drainage. Which nerve conveys its somatic sensation?

A. Phrenic nerveB. Intercostal nerveC. Vagus nerveD. Long thoracic nerveE. Greater splanchnic nerve

View detailed explanation, examiner trap and viva

Correct answer: B. Intercostal nerve.

Why correct: Costal parietal pleura receives somatic innervation from intercostal nerves corresponding to the local thoracic wall.

Why the other options are incorrect:

A. Phrenic nerve: Supplies central diaphragmatic and mediastinal pleura, not lateral costal pleura.

C. Vagus nerve: Provides visceral autonomic afferents from intrathoracic organs.

D. Long thoracic nerve: Motor to serratus anterior, not the sensory nerve of costal pleura.

E. Greater splanchnic nerve: Carries abdominal visceral fibres rather than costal pleural pain.

Exam pearl: Costal parietal pleural pain follows intercostal dermatomes.

Examiner trap: Different pleural surfaces do not share the same sensory supply.

Viva extension — What supplies central diaphragmatic pleura? Answer: Phrenic nerve (C3–C5).

Question 3 of 40 • Pleural referred pain

Q03. A patient with irritation of central diaphragmatic pleura experiences pain at the ipsilateral shoulder tip. Which nerve mediates this referral?

A. Intercostobrachial nerveB. Long thoracic nerveC. Phrenic nerveD. Vagus nerveE. Thoracodorsal nerve

View detailed explanation, examiner trap and viva

Correct answer: C. Phrenic nerve.

Why correct: Phrenic afferents enter spinal levels C3–C5, overlapping shoulder-tip sensory territories and causing referred pain.

Why the other options are incorrect:

A. Intercostobrachial nerve: Supplies skin of axilla and medial arm rather than diaphragm.

B. Long thoracic nerve: Motor supply to serratus anterior.

D. Vagus nerve: Provides visceral autonomic pathways but not the classic C3–C5 shoulder referral.

E. Thoracodorsal nerve: Motor innervation of latissimus dorsi.

Exam pearl: Shoulder-tip pain can originate from diaphragm irritation.

Examiner trap: Phrenic sensory referral is not the same as intercostal costal-pleura pain.

Viva extension — What is the motor root value of the phrenic nerve? Answer: C3–C5, mainly C4.

Question 4 of 40 • Rib neurovascular order

Q04. Within the usual intercostal costal groove, what is the structure order from superior to inferior?

A. Artery, vein, nerveB. Nerve, artery, veinC. Vein, nerve, arteryD. Vein, artery, nerveE. Artery, nerve, vein

View detailed explanation, examiner trap and viva

Correct answer: D. Vein, artery, nerve.

Why correct: The main intercostal bundle is arranged VAN, with the vein highest and nerve lowest.

Why the other options are incorrect:

A. Artery, vein, nerve: Reverses the superior positions of vein and artery.

B. Nerve, artery, vein: Reverses VAN and puts the nerve highest.

C. Vein, nerve, artery: Places nerve above artery, contrary to the classic relation.

E. Artery, nerve, vein: Puts vein inferior rather than superior.

Exam pearl: VAN from superior to inferior.

Examiner trap: An additional collateral bundle may run close to the opposite rib margin.

Viva extension — Where does the principal bundle lie? Answer: In the costal groove along the inferior rib margin.

Question 5 of 40 • Lung hilum

Q05. During a thoracotomy, which nerve normally passes anterior to the lung root?

A. Vagus nerveB. Recurrent laryngeal nerveC. Greater splanchnic nerveD. Intercostal nerveE. Phrenic nerve

View detailed explanation, examiner trap and viva

Correct answer: E. Phrenic nerve.

Why correct: The phrenic nerve descends in front of the lung root on pericardium; vagus passes behind the lung root.

Why the other options are incorrect:

A. Vagus nerve: Runs posterior to the hilum and contributes to pulmonary and oesophageal plexuses.

B. Recurrent laryngeal nerve: Loops at the subclavian artery or arch of aorta rather than crossing the hilum anteriorly.

C. Greater splanchnic nerve: Arises from thoracic sympathetic chain and descends toward the abdomen.

D. Intercostal nerve: Runs in a chest wall interspace, not anterior to lung root.

Exam pearl: Phrenic front, vagus back.

Examiner trap: Do not identify both nerves as posterior to hilum.

Viva extension — Which muscle is paralysed after phrenic injury? Answer: Ipsilateral hemidiaphragm.

Question 6 of 40 • Thoracic duct

Q06. After left neck dissection, chylous drainage collects near the venous angle. Where does the thoracic duct normally terminate?

A. Junction of left internal jugular and subclavian veinsB. Right venous angleC. Azygos veinD. Superior vena cava directlyE. Left pulmonary vein

View detailed explanation, examiner trap and viva

Correct answer: A. Junction of left internal jugular and subclavian veins.

Why correct: The duct typically drains into the left venous angle after collecting lymph from much of the body.

Why the other options are incorrect:

B. Right venous angle: Usually receives the right lymphatic duct, not the thoracic duct.

C. Azygos vein: A systemic vein and not the normal terminal lymphatic drainage point.

D. Superior vena cava directly: Thoracic duct ordinarily joins the left venous angle.

E. Left pulmonary vein: Pulmonary venous return is not a lymphatic outlet.

Exam pearl: Chylous leak after left neck surgery suggests thoracic duct injury.

Examiner trap: There can be variable terminal anatomy, but left venous angle is canonical.

Viva extension — What are common clues of chylothorax? Answer: Milky pleural drainage and high pleural-fluid triglycerides.

Question 7 of 40 • Recurrent laryngeal anatomy

Q07. In aortic arch surgery, a nerve loops under the aortic arch beside ligamentum arteriosum. Which nerve is it?

A. Right recurrent laryngeal nerveB. Left recurrent laryngeal nerveC. Left phrenic nerveD. Left hypoglossal nerveE. Left glossopharyngeal nerve

View detailed explanation, examiner trap and viva

Correct answer: B. Left recurrent laryngeal nerve.

Why correct: The left recurrent laryngeal nerve branches from the vagus, loops under the aortic arch and ascends in the tracheoesophageal groove.

Why the other options are incorrect:

A. Right recurrent laryngeal nerve: Loops beneath right subclavian artery rather than the aortic arch.

C. Left phrenic nerve: Passes anterior to lung root toward the diaphragm rather than looping under arch.

D. Left hypoglossal nerve: A tongue motor nerve in the neck, not mediastinum.

E. Left glossopharyngeal nerve: Supplies pharyngeal functions and does not loop below the aorta.

Exam pearl: Aortic arch aneurysm may cause left vocal cord palsy.

Examiner trap: Right and left recurrent laryngeal nerves loop around different structures.

Viva extension — What is the right recurrent laryngeal loop? Answer: Right subclavian artery.

Question 8 of 40 • Cardiac surface

Q08. A stab wound adjacent to the anterior left parasternal region threatens which cardiac chamber most commonly forming the anterior surface?

A. Left atriumB. Right atriumC. Right ventricleD. Left ventricleE. Coronary sinus

View detailed explanation, examiner trap and viva

Correct answer: C. Right ventricle.

Why correct: Much of the sternocostal cardiac surface is right ventricle, making it exposed in anterior penetrating injury.

Why the other options are incorrect:

A. Left atrium: Located chiefly posteriorly and forms cardiac base.

B. Right atrium: Forms much of the right cardiac border, less of the anterior central surface.

D. Left ventricle: Contributes apex and left border, though parts of anterior surface are LV.

E. Coronary sinus: A venous channel on the posterior atrioventricular groove, not a chamber.

Exam pearl: Right ventricle forms most of sternocostal surface.

Examiner trap: Left-sided skin wound does not automatically mean left ventricle injury.

Viva extension — Which chamber forms the apex? Answer: Left ventricle.

Question 9 of 40 • Coronary dominance

Q09. A coronary angiogram shows the posterior descending artery arising from the right coronary artery. How is coronary dominance described?

A. Left dominantB. Codominant by definitionC. Right atrial dominantD. Right dominantE. Anterior dominant

View detailed explanation, examiner trap and viva

Correct answer: D. Right dominant.

Why correct: Dominance is defined by which coronary system gives rise to the posterior descending artery in the posterior interventricular groove.

Why the other options are incorrect:

A. Left dominant: Would place PDA origin in circumflex/left coronary distribution.

B. Codominant by definition: Codominance depends on shared posterior supply, not PDA from RCA alone.

C. Right atrial dominant: Describes a chamber, not coronary vascular definition.

E. Anterior dominant: No standard coronary dominance label based on anterior interventricular artery.

Exam pearl: Dominance = PDA origin.

Examiner trap: The largest coronary artery is not necessarily the dominant system.

Viva extension — Which artery is called the LAD? Answer: Anterior interventricular branch of the left coronary artery.

Question 10 of 40 • LAD course

Q10. Which coronary artery traverses the anterior interventricular groove?

A. Posterior descending arteryB. Right marginal arteryC. Circumflex arteryD. Sinoatrial nodal arteryE. Left anterior descending artery

View detailed explanation, examiner trap and viva

Correct answer: E. Left anterior descending artery.

Why correct: The LAD runs in the anterior interventricular sulcus toward the apex and supplies key anterior septal territories.

Why the other options are incorrect:

A. Posterior descending artery: Occupies the posterior interventricular groove.

B. Right marginal artery: Follows the acute margin of right ventricle.

C. Circumflex artery: Courses in left atrioventricular groove.

D. Sinoatrial nodal artery: A variable nodal branch not identified by anterior groove.

Exam pearl: Anterior groove: LAD; posterior groove: PDA.

Examiner trap: Coronary dominance is not defined by LAD origin.

Viva extension — Which branch often supplies anterior septum? Answer: Septal perforators from the LAD.

Question 11 of 40 • Diaphragmatic hiatus

Q11. During repair of a sliding hiatus hernia, the surgeon examines the muscular passage for the oesophagus. What vertebral level is classically assigned to it?

A. T10B. T8C. T12D. L1E. T6

View detailed explanation, examiner trap and viva

Correct answer: A. T10.

Why correct: The oesophagus and vagal trunks travel through the oesophageal hiatus near T10.

Why the other options are incorrect:

B. T8: More associated with IVC in central tendon.

C. T12: More associated with aortic passage posterior to diaphragm.

D. L1: Below the usual diaphragmatic hiatus levels.

E. T6: Above typical diaphragmatic opening levels.

Exam pearl: T8 caval, T10 oesophageal, T12 aortic.

Examiner trap: The vertebral levels are anatomical guides, not precise fixed patient measurements.

Viva extension — What travels with oesophagus? Answer: Anterior and posterior vagal trunks.

Question 12 of 40 • Aortic passage

Q12. Which vessel passes behind the diaphragm through the aortic hiatus at approximately T12?

A. Inferior vena cavaB. Descending aortaC. Superior vena cavaD. Pulmonary trunkE. Azygos arch

View detailed explanation, examiner trap and viva

Correct answer: B. Descending aorta.

Why correct: Aorta passes posterior to diaphragm at T12 accompanied by thoracic duct; unlike IVC, it does not traverse central tendon.

Why the other options are incorrect:

A. Inferior vena cava: Passes through central tendon near T8.

C. Superior vena cava: Drains into right atrium above diaphragm.

D. Pulmonary trunk: In pericardium and does not cross diaphragm.

E. Azygos arch: Arches over right pulmonary hilum into SVC.

Exam pearl: Aortic hiatus is posterior and T12.

Examiner trap: Do not confuse the IVC opening with aortic hiatus.

Viva extension — Which lymphatic structure accompanies aorta? Answer: Thoracic duct.

Question 13 of 40 • Congenital diaphragmatic hernia

Q13. A newborn has severe respiratory distress and radiographs show bowel in the left hemithorax through a posterolateral diaphragmatic defect. Which defect is most likely?

A. Morgagni herniaB. Sliding hiatus herniaC. Bochdalek herniaD. OmphaloceleE. Gastroschisis

View detailed explanation, examiner trap and viva

Correct answer: C. Bochdalek hernia.

Why correct: Failure of posterolateral pleuroperitoneal canal closure produces Bochdalek diaphragmatic hernia and pulmonary hypoplasia.

Why the other options are incorrect:

A. Morgagni hernia: Usually anterior parasternal diaphragmatic defect.

B. Sliding hiatus hernia: Occurs through oesophageal hiatus rather than posterolateral defect.

D. Omphalocele: Abdominal wall defect at umbilicus, not diaphragm.

E. Gastroschisis: Paraumbilical full-thickness abdominal wall defect.

Exam pearl: Left posterolateral neonatal diaphragmatic defect = Bochdalek.

Examiner trap: Do not label every congenital thoracic bowel herniation as hiatus hernia.

Viva extension — What determines neonatal severity? Answer: Degree of pulmonary hypoplasia and pulmonary hypertension.

Question 14 of 40 • Thoracic duct location

Q14. Oesophagectomy is followed by high-output milky chest drainage. Which structure was most likely injured?

A. Phrenic nerveB. Recurrent laryngeal nerveC. Intercostobrachial nerveD. Thoracic ductE. Coronary sinus

View detailed explanation, examiner trap and viva

Correct answer: D. Thoracic duct.

Why correct: Injury of the thoracic duct during posterior mediastinal dissection may cause a postoperative chylothorax.

Why the other options are incorrect:

A. Phrenic nerve: Would primarily cause ipsilateral diaphragmatic weakness.

B. Recurrent laryngeal nerve: Would primarily affect voice and aspiration risk.

C. Intercostobrachial nerve: Would cause medial upper-arm sensory symptoms.

E. Coronary sinus: Cardiac venous structure, not a source of lymphatic chyle.

Exam pearl: Chylothorax after oesophageal surgery suggests duct injury.

Examiner trap: Milky drainage is supportive but confirm with fluid studies.

Viva extension — Where does duct ultimately drain? Answer: Usually into left venous angle.

Question 15 of 40 • Ureter and uterine artery

Q15. During hysterectomy, the surgeon ligates the uterine artery close to cervix. Which structure passes inferior to it and must be protected?

A. Obturator nerveB. Round ligamentC. External iliac veinD. Hypogastric nerveE. Ureter

View detailed explanation, examiner trap and viva

Correct answer: E. Ureter.

Why correct: The distal ureter courses beneath the uterine artery close to cervix, making it vulnerable during vessel ligation.

Why the other options are incorrect:

A. Obturator nerve: Runs on lateral pelvic wall and through obturator canal, not immediately beneath uterine artery at cervix.

B. Round ligament: Runs from uterine horn toward deep inguinal ring, not the water-under-bridge crossing.

C. External iliac vein: Lies near pelvic brim and does not form the classic cervical crossing.

D. Hypogastric nerve: Carries pelvic autonomic fibres but is not the structure directly crossed by uterine artery.

Exam pearl: Water under the bridge: ureter under uterine artery.

Examiner trap: The ureter can be damaged by ligation, traction or thermal injury.

Viva extension — Where does the ureter enter bladder? Answer: Posterolateral bladder wall with an oblique intramural course.

Question 16 of 40 • Ureter in male pelvis

Q16. During surgery near the posterolateral bladder in a man, which structure passes superior to the distal ureter?

A. Ductus deferensB. Spermatic cord fasciaC. Femoral arteryD. Inferior epigastric veinE. Median umbilical ligament

View detailed explanation, examiner trap and viva

Correct answer: A. Ductus deferens.

Why correct: The ductus deferens crosses above the terminal ureter as it approaches seminal vesicle and bladder.

Why the other options are incorrect:

B. Spermatic cord fascia: Surrounds cord structures in inguinal canal, not a crossing over distal pelvic ureter.

C. Femoral artery: Passes anteriorly beneath inguinal ligament into thigh.

D. Inferior epigastric vein: An abdominal wall vessel near internal ring, not the distal ureter crossing.

E. Median umbilical ligament: Remnant of urachus in midline from bladder apex.

Exam pearl: Male pelvis: vas deferens crosses over ureter.

Examiner trap: Do not interchange male vas-deferens crossing with female uterine-artery crossing.

Viva extension — What are the paired glands close to this junction? Answer: Seminal vesicles.

Question 17 of 40 • Pelvic ureter at brim

Q17. During pelvic dissection, the ureter is identified where it crosses into the true pelvis. Which vascular landmark is commonly related here?

A. Splenic veinB. Bifurcation of common iliac arteryC. Superior mesenteric artery originD. Popliteal arteryE. Inferior mesenteric vein

View detailed explanation, examiner trap and viva

Correct answer: B. Bifurcation of common iliac artery.

Why correct: The ureter usually crosses anterior to the common iliac bifurcation or proximal external iliac artery at the pelvic brim.

Why the other options are incorrect:

A. Splenic vein: Upper abdominal portal tributary near pancreas.

C. Superior mesenteric artery origin: Arises from upper aorta near L1, far cranial to pelvic brim.

D. Popliteal artery: Behind knee, not pelvic brim.

E. Inferior mesenteric vein: Upper left abdominal venous drainage, not a pelvic brim landmark.

Exam pearl: Trace ureter anterior to iliac vessel region at pelvic brim.

Examiner trap: Exact ureteric crossing can vary over common versus external iliac.

Viva extension — Is pelvic ureter intraperitoneal? Answer: No; ureter is retroperitoneal.

Question 18 of 40 • Pudendal nerve

Q18. A pudendal block is administered transvaginally using an important bony landmark. Which landmark is targeted?

A. Anterior superior iliac spineB. Pubic symphysisC. Ischial spineD. Greater trochanterE. Sacral promontory

View detailed explanation, examiner trap and viva

Correct answer: C. Ischial spine.

Why correct: The pudendal nerve passes close to the ischial spine and sacrospinous ligament on its course to perineum.

Why the other options are incorrect:

A. Anterior superior iliac spine: Superficial anterior pelvis and not near pudendal course.

B. Pubic symphysis: Anterior midline pelvic joint far from pudendal course at spine.

D. Greater trochanter: Lateral proximal femoral landmark, not for pudendal block.

E. Sacral promontory: Midline posterior pelvic brim, not typical pudendal-block reference.

Exam pearl: Pudendal nerve block landmark is the ischial spine.

Examiner trap: Do not confuse this somatic nerve with pelvic splanchnic parasympathetics.

Viva extension — Root values? Answer: S2–S4.

Question 19 of 40 • Pudendal route

Q19. After exiting pelvis inferior to piriformis, the pudendal nerve re-enters the perineal region through which foramen?

A. Greater sciatic foramen againB. Obturator canalC. Femoral canalD. Lesser sciatic foramenE. Inguinal canal

View detailed explanation, examiner trap and viva

Correct answer: D. Lesser sciatic foramen.

Why correct: The nerve initially leaves through greater sciatic foramen, loops around sacrospinous ligament and returns via lesser sciatic foramen.

Why the other options are incorrect:

A. Greater sciatic foramen again: This is the first exit from pelvis, not the return into perineum.

B. Obturator canal: Transmits obturator nerve and vessels to medial thigh.

C. Femoral canal: A groin fascial space medial to femoral vein.

E. Inguinal canal: Transmits cord or round ligament structures, not pudendal nerve.

Exam pearl: Greater out, lesser in.

Examiner trap: Course also involves Alcock canal, which is not itself a sciatic foramen.

Viva extension — Where does nerve run in perineum? Answer: Pudendal (Alcock) canal along obturator internus fascia.

Question 20 of 40 • Puborectalis

Q20. An anorectal surgical injury weakens the muscular sling maintaining the anorectal angle. Which muscle is injured?

A. PiriformisB. Obturator externusC. Gluteus minimusD. Rectus abdominisE. Puborectalis

View detailed explanation, examiner trap and viva

Correct answer: E. Puborectalis.

Why correct: Puborectalis encircles anorectal junction and supports the forward anorectal bend necessary for continence.

Why the other options are incorrect:

A. Piriformis: Lateral pelvic wall muscle and sciatic-foramen landmark.

B. Obturator externus: Hip external rotator outside pelvis.

C. Gluteus minimus: Hip abductor and stabiliser rather than anal sphincter.

D. Rectus abdominis: Abdominal wall flexor not producing anorectal sling.

Exam pearl: Puborectalis maintains anorectal angle.

Examiner trap: External anal sphincter is distinct from levator-ani puborectalis component.

Viva extension — To which muscular group does it belong? Answer: Levator ani.

Question 21 of 40 • Anal canal drainage

Q21. A squamous cell carcinoma arises well below the pectinate line in the distal anal canal. Which nodes are a major first drainage basin?

A. Superficial inguinal nodesB. Para-aortic nodesC. Celiac nodesD. Superior mesenteric nodesE. Axillary nodes

View detailed explanation, examiner trap and viva

Correct answer: A. Superficial inguinal nodes.

Why correct: Lymph from anal canal below pectinate line commonly drains to superficial inguinal nodes.

Why the other options are incorrect:

B. Para-aortic nodes: More distant retroperitoneal nodes rather than first-tier inferior anal drainage.

C. Celiac nodes: Drain foregut viscera.

D. Superior mesenteric nodes: Drain midgut rather than inferior anal canal.

E. Axillary nodes: Drain upper limb and thoracic wall regions.

Exam pearl: Below pectinate line: superficial inguinal nodes.

Examiner trap: Above pectinate line drainage predominantly follows internal iliac pathways, with rectal-region variations.

Viva extension — How does sensation change across pectinate line? Answer: Below somatic pain, above visceral sensation.

Question 22 of 40 • Anal canal pain

Q22. An acutely thrombosed external haemorrhoid below pectinate line is very painful. Which sensory pathway best explains this?

A. Vagus nerveB. Inferior rectal branches of pudendal nerveC. Greater splanchnic nerveD. Phrenic nerveE. Iliohypogastric nerve

View detailed explanation, examiner trap and viva

Correct answer: B. Inferior rectal branches of pudendal nerve.

Why correct: Distal anal canal and perianal skin receive somatic sensation via inferior rectal nerves, making lesions distinctly painful.

Why the other options are incorrect:

A. Vagus nerve: Autonomic innervation of thoracoabdominal viscera, not perianal skin.

C. Greater splanchnic nerve: Upper abdominal visceral fibres, not somatic anal pain.

D. Phrenic nerve: Supplies diaphragm and central pleura.

E. Iliohypogastric nerve: Lower abdominal wall sensation, not primary perianal sensory supply.

Exam pearl: External haemorrhoids are below pectinate line and can be painful.

Examiner trap: Pain does not define all hemorrhoids; location and complications matter.

Viva extension — Origin of inferior rectal nerves? Answer: Usually pudendal nerve branches.

Question 23 of 40 • Bladder trigone

Q23. Which structures define the three corners of the bladder trigone?

A. Two ejaculatory ducts and urethral openingB. Bladder apex, dome and umbilicusC. Two ureteric orifices and internal urethral openingD. Two obturator foramina and internal osE. Two renal pelves and external urethral meatus

View detailed explanation, examiner trap and viva

Correct answer: C. Two ureteric orifices and internal urethral opening.

Why correct: The trigone is a smooth triangular area between paired ureteric openings and bladder outlet.

Why the other options are incorrect:

A. Two ejaculatory ducts and urethral opening: Ejaculatory ducts empty into prostatic urethra, not bladder trigone.

B. Bladder apex, dome and umbilicus: These are not the trigone boundary openings.

D. Two obturator foramina and internal os: Unrelated pelvic skeletal and cervical landmarks.

E. Two renal pelves and external urethral meatus: These are distant anatomical openings.

Exam pearl: Trigone = two ureters plus internal urethral opening.

Examiner trap: The external urethral meatus is not a trigone landmark.

Viva extension — What prevents reflux along distal ureter? Answer: Its oblique intramural passage through bladder wall contributes to antireflux function.

Question 24 of 40 • Pelvic splanchnic nerves

Q24. A nerve injury impairs parasympathetic bladder detrusor contraction and erection. Which spinal segments contribute to the pelvic splanchnic nerves?

A. T1–T4B. T5–T9C. L1–L2D. S2–S4E. C3–C5

View detailed explanation, examiner trap and viva

Correct answer: D. S2–S4.

Why correct: Pelvic splanchnics arise from S2–S4 and supply parasympathetic pathways to pelvic viscera.

Why the other options are incorrect:

A. T1–T4: Predominantly upper sympathetic levels.

B. T5–T9: Thoracic sympathetic splanchnic contributions to abdominal viscera.

C. L1–L2: Predominantly sympathetic lumbar outflow rather than pelvic parasympathetic.

E. C3–C5: Phrenic motor roots for diaphragm.

Exam pearl: Pelvic splanchnics = S2–S4 parasympathetic.

Examiner trap: Pudendal nerve also S2–S4 but is chiefly somatic, not pelvic visceral parasympathetic.

Viva extension — Which fibres mediate voluntary external sphincter control? Answer: Somatic pudendal motor fibres.

Question 25 of 40 • Rectum arterial supply

Q25. A pelvic surgeon identifies the artery descending from IMA to supply upper rectum. Which vessel is it?

A. Middle rectal arteryB. Inferior rectal arteryC. Right gastroepiploic arteryD. Inferior epigastric arteryE. Superior rectal artery

View detailed explanation, examiner trap and viva

Correct answer: E. Superior rectal artery.

Why correct: The superior rectal artery is the terminal continuation of inferior mesenteric artery into pelvis.

Why the other options are incorrect:

A. Middle rectal artery: Typically arises from internal iliac system with variable presence.

B. Inferior rectal artery: Arises from internal pudendal system to distal canal.

C. Right gastroepiploic artery: Supplies greater curvature of stomach.

D. Inferior epigastric artery: Supplies anterior abdominal wall.

Exam pearl: Superior rectal = IMA; inferior rectal = internal pudendal.

Examiner trap: Rectum has collateral arterial sources; do not assume a single feeder.

Viva extension — Which rectal vessel contributes systemic portosystemic venous communication? Answer: Rectal venous plexus, especially superior rectal (portal) versus middle/inferior (systemic) drainage.

Question 26 of 40 • Internal pudendal artery

Q26. Which artery accompanies the pudendal nerve through the lesser sciatic foramen into the perineum?

A. Internal pudendal arteryB. External iliac arteryC. Obturator arteryD. Inferior mesenteric arteryE. Superior gluteal artery

View detailed explanation, examiner trap and viva

Correct answer: A. Internal pudendal artery.

Why correct: An anterior-division internal iliac branch, the internal pudendal artery travels with pudendal nerve to perineum.

Why the other options are incorrect:

B. External iliac artery: Continues to femoral artery beneath inguinal ligament.

C. Obturator artery: Usually enters obturator canal to supply medial thigh.

D. Inferior mesenteric artery: Supplies hindgut and originates directly from aorta.

E. Superior gluteal artery: Exits greater sciatic foramen above piriformis to gluteal region.

Exam pearl: Internal pudendal artery accompanies pudendal nerve.

Examiner trap: Superior gluteal is not the perineal arterial supply via lesser foramen.

Viva extension — Parent vessel? Answer: Internal iliac artery, usually anterior division.

Question 27 of 40 • Lesser sac

Q27. A posterior gastric ulcer perforates into a potential space behind the stomach. Which space is involved?

A. Hepatorenal recessB. Lesser sac (omental bursa)C. Rectovesical pouchD. Paracolic gutterE. Extraperitoneal space of Retzius

View detailed explanation, examiner trap and viva

Correct answer: B. Lesser sac (omental bursa).

Why correct: The lesser sac lies posterior to the stomach and lesser omentum, anterior to pancreas.

Why the other options are incorrect:

A. Hepatorenal recess: Between liver and right kidney, not directly posterior to stomach.

C. Rectovesical pouch: Pelvic peritoneal recess in male.

D. Paracolic gutter: Lateral to colon and not immediately posterior to stomach.

E. Extraperitoneal space of Retzius: Anterior to bladder and behind pubic symphysis.

Exam pearl: Behind the stomach = lesser sac.

Examiner trap: The lesser sac communicates with greater sac through epiploic foramen.

Viva extension — What lies posterior to lesser sac? Answer: Pancreas and adjacent posterior abdominal structures.

Question 28 of 40 • Epiploic foramen

Q28. A surgeon inserts a finger through epiploic foramen. Which structure forms its anterior boundary?

A. Inferior vena cavaB. Caudate lobe of liverC. Hepatoduodenal ligament containing portal triadD. First part of duodenumE. Transverse mesocolon

View detailed explanation, examiner trap and viva

Correct answer: C. Hepatoduodenal ligament containing portal triad.

Why correct: Free edge of lesser omentum lies anterior to foramen and encloses duct, artery, and portal vein.

Why the other options are incorrect:

A. Inferior vena cava: Forms posterior boundary rather than anterior.

B. Caudate lobe of liver: Forms superior boundary.

D. First part of duodenum: Forms inferior boundary.

E. Transverse mesocolon: Not a direct border of epiploic foramen.

Exam pearl: Anterior boundary = hepatoduodenal ligament; posterior = IVC.

Examiner trap: Do not confuse foramen boundaries with the portal-triad arrangement within its anterior border.

Viva extension — Which liver lobe is superior? Answer: Caudate lobe.

Question 29 of 40 • Pringle manoeuvre

Q29. Severe liver trauma leads a surgeon to compress the free edge of lesser omentum. Which structures are primarily compressed?

A. Hepatic veins and IVCB. Splenic artery aloneC. Inferior mesenteric artery aloneD. Portal vein and hepatic artery inflow with bile ductE. Renal arteries

View detailed explanation, examiner trap and viva

Correct answer: D. Portal vein and hepatic artery inflow with bile duct.

Why correct: The Pringle manoeuvre compresses hepatoduodenal ligament containing portal vein, proper hepatic artery and bile duct.

Why the other options are incorrect:

A. Hepatic veins and IVC: These are outflow structures posterior to liver, not within ligament.

B. Splenic artery alone: Runs toward spleen along pancreas.

C. Inferior mesenteric artery alone: Supplies hindgut and arises from aorta.

E. Renal arteries: Retroperitoneal branches of abdominal aorta.

Exam pearl: Pringle controls portal inflow, not hepatic venous outflow.

Examiner trap: Persistent bleeding despite adequate inflow occlusion suggests hepatic venous or caval injury.

Viva extension — What makes the portal triad? Answer: Portal vein, proper hepatic artery and bile duct.

Question 30 of 40 • Portal triad orientation

Q30. In the hepatoduodenal ligament, which structure generally lies posterior to both proper hepatic artery and common bile duct?

A. Cystic ductB. Proper hepatic arteryC. Common bile ductD. Hepatic veinE. Portal vein

View detailed explanation, examiner trap and viva

Correct answer: E. Portal vein.

Why correct: Portal vein is posterior; bile duct generally lies anterior right, hepatic artery anterior left.

Why the other options are incorrect:

A. Cystic duct: Joins common hepatic duct and is not the posterior main portal triad component.

B. Proper hepatic artery: Is typically anteromedial to portal vein.

C. Common bile duct: Typically anterolateral rather than posterior.

D. Hepatic vein: Drains into IVC outside ligament.

Exam pearl: Portal vein behind; duct right and artery left anteriorly.

Examiner trap: Anatomical variants exist especially in arterial branching.

Viva extension — Which duct is usually anterior right? Answer: Common bile duct.

Question 31 of 40 • Hepatocystic triangle

Q31. During laparoscopic cholecystectomy, what forms the superior boundary of the modern hepatocystic triangle?

A. Inferior surface of liverB. Hepatoduodenal ligament posterior surfaceC. Duodenal bulbD. Right kidneyE. Gallbladder fundus

View detailed explanation, examiner trap and viva

Correct answer: A. Inferior surface of liver.

Why correct: Modern cystohepatic triangle bounded by cystic duct, common hepatic duct and inferior liver edge.

Why the other options are incorrect:

B. Hepatoduodenal ligament posterior surface: Contains portal structures but is not the named superior boundary.

C. Duodenal bulb: Inferior to portal region, not triangle roof.

D. Right kidney: Posterior retroperitoneal organ not a triangle boundary.

E. Gallbladder fundus: Distal gallbladder portion outside the ductal triangle.

Exam pearl: Modern hepatocystic triangle roof = inferior liver surface.

Examiner trap: Historical Calot triangle may name cystic artery as border; clarify terminology.

Viva extension — What is the operative safety objective? Answer: Critical view of safety identifying only two structures entering gallbladder after adequate dissection.

Question 32 of 40 • Short gastric arteries

Q32. During splenectomy, ligation of vessels in the gastrosplenic ligament risks compromising fundal perfusion. Which vessels are involved?

A. Left gastric arteryB. Short gastric arteriesC. Right gastric arteryD. Inferior mesenteric arteryE. Middle colic artery

View detailed explanation, examiner trap and viva

Correct answer: B. Short gastric arteries.

Why correct: Branches of splenic artery travel through gastrosplenic ligament to fundus.

Why the other options are incorrect:

A. Left gastric artery: Primarily supplies lesser curvature within lesser omentum.

C. Right gastric artery: Supplies lesser curvature, commonly from hepatic system.

D. Inferior mesenteric artery: Supplies hindgut, not gastric fundus.

E. Middle colic artery: Supplies transverse colon from SMA.

Exam pearl: Short gastrics run in gastrosplenic ligament.

Examiner trap: Do not confuse gastrosplenic with splenorenal ligament containing splenic vessels near hilum and pancreatic tail.

Viva extension — Parent artery? Answer: Splenic artery.

Question 33 of 40 • Coeliac artery

Q33. A patient has proximal foregut ischaemia. Which artery is the usual primary trunk supplying stomach, liver and spleen?

A. Superior mesenteric arteryB. Inferior mesenteric arteryC. Coeliac trunkD. Internal iliac arteryE. Median sacral artery

View detailed explanation, examiner trap and viva

Correct answer: C. Coeliac trunk.

Why correct: Coeliac trunk typically divides into left gastric, common hepatic and splenic arteries.

Why the other options are incorrect:

A. Superior mesenteric artery: Supplies midgut including distal duodenum through proximal transverse colon.

B. Inferior mesenteric artery: Supplies hindgut.

D. Internal iliac artery: Supplies pelvic organs and walls.

E. Median sacral artery: Small branch descending near sacrum.

Exam pearl: Coeliac supplies foregut; SMA midgut; IMA hindgut.

Examiner trap: Foregut/midgut vascular transition is in duodenum around major papilla.

Viva extension — Three usual coeliac branches? Answer: Left gastric, common hepatic, splenic.

Question 34 of 40 • Uncinate process

Q34. During pancreaticoduodenectomy, the uncinate process is dissected from vessels passing immediately anterior to it. Which vascular complex is relevant?

A. Inferior mesenteric vein onlyB. Right renal artery onlyC. Azygos veinD. Superior mesenteric vesselsE. Common iliac vessels

View detailed explanation, examiner trap and viva

Correct answer: D. Superior mesenteric vessels.

Why correct: The uncinate process projects posterior to superior mesenteric artery and vein, a key surgical plane.

Why the other options are incorrect:

A. Inferior mesenteric vein only: Joins splenic vein more superiorly; not the primary uncinate crossing.

B. Right renal artery only: Posterior retroperitoneal relation, not the characteristic anterior uncinate vessels.

C. Azygos vein: Thoracic venous structure.

E. Common iliac vessels: Located near pelvic brim, well below pancreas.

Exam pearl: Uncinate lies behind SMA/SMV.

Examiner trap: SMA and SMV are two separate vessels; relationship can vary by slice/level.

Viva extension — Where does portal vein form? Answer: Behind neck of pancreas from SMV and splenic vein.

Question 35 of 40 • Portal vein formation

Q35. At pancreatic neck, which two veins usually unite to create portal vein?

A. IVC and renal veinB. Inferior mesenteric artery and splenic arteryC. Right gastric vein and hepatic veinD. Azygos and hemiazygos veinsE. Splenic vein and superior mesenteric vein

View detailed explanation, examiner trap and viva

Correct answer: E. Splenic vein and superior mesenteric vein.

Why correct: Portal vein forms posterior to neck of pancreas from SMV and splenic vein union.

Why the other options are incorrect:

A. IVC and renal vein: Form systemic venous drainage rather than portal trunk.

B. Inferior mesenteric artery and splenic artery: Arteries do not join to form a vein.

C. Right gastric vein and hepatic vein: Do not form main portal vein at pancreas.

D. Azygos and hemiazygos veins: Thoracic systemic venous channels.

Exam pearl: SMV + splenic behind neck = portal vein.

Examiner trap: IMV often drains into splenic vein but varies.

Viva extension — Which vein often enters splenic vein superiorly? Answer: Inferior mesenteric vein, although variants are common.

Question 36 of 40 • Major duodenal papilla

Q36. A stone obstructs the hepatopancreatic ampulla. In which part of duodenum does the major papilla open?

A. Second (descending) partB. First partC. Third partD. Fourth partE. Jejunum

View detailed explanation, examiner trap and viva

Correct answer: A. Second (descending) part.

Why correct: The common bile duct and main pancreatic duct usually join at ampulla and open on major papilla in second part.

Why the other options are incorrect:

B. First part: Duodenal bulb is proximal to major papilla.

C. Third part: Crosses anterior to aorta and IVC; not usual papilla site.

D. Fourth part: Ascends to duodenojejunal flexure.

E. Jejunum: Further distal beyond ligament of Treitz.

Exam pearl: Major papilla is in D2.

Examiner trap: An accessory pancreatic duct may drain at minor papilla above the major papilla.

Viva extension — Which sphincter regulates ampulla flow? Answer: Sphincter of Oddi.

Question 37 of 40 • Mesenteric territories

Q37. A branch occlusion affects distal ileum and caecum. Which parent artery supplies this midgut territory?

A. Coeliac trunkB. Superior mesenteric arteryC. Inferior mesenteric arteryD. Renal arteryE. Internal iliac artery

View detailed explanation, examiner trap and viva

Correct answer: B. Superior mesenteric artery.

Why correct: SMA gives ileocolic and intestinal branches to distal ileum and caecum.

Why the other options are incorrect:

A. Coeliac trunk: Supplies foregut principally.

C. Inferior mesenteric artery: Supplies hindgut, including distal transverse colon onwards.

D. Renal artery: Supplies kidney.

E. Internal iliac artery: Supplies pelvic tissues, not ileocaecal gut.

Exam pearl: Ileocaecal region is SMA territory.

Examiner trap: SMA territory extends to proximal two-thirds transverse colon; boundaries vary somewhat anatomically.

Viva extension — Which SMA branch supplies caecum? Answer: Ileocolic artery branches.

Question 38 of 40 • Appendix base

Q38. During appendicectomy, the appendix is not initially apparent beneath inflammatory adhesions. Which surface feature most reliably leads to its base?

A. Splenic flexureB. Attachment of greater omentum to stomachC. Convergence of three taeniae coliD. Ileojejunal junctionE. Pancreatic tail

View detailed explanation, examiner trap and viva

Correct answer: C. Convergence of three taeniae coli.

Why correct: Longitudinal smooth-muscle bands of caecum converge at the origin of vermiform appendix.

Why the other options are incorrect:

A. Splenic flexure: Distant left colonic junction.

B. Attachment of greater omentum to stomach: Foregut relation, not appendix base.

D. Ileojejunal junction: No such named fixed landmark at caecum.

E. Pancreatic tail: Left upper abdominal organ near splenic hilum.

Exam pearl: Trace the three taeniae coli to appendix base.

Examiner trap: Appendix tip position varies; base is comparatively constant.

Viva extension — What arterial vessel supplies appendix? Answer: Appendicular artery, commonly branch of ileocolic via inferior division.

Question 39 of 40 • Secondarily retroperitoneal

Q39. In colonic mobilisation, which bowel segment is classically secondarily retroperitoneal and fused to posterior abdominal wall?

A. JejunumB. Transverse colonC. Sigmoid colonD. Ascending colonE. Caecum exclusively

View detailed explanation, examiner trap and viva

Correct answer: D. Ascending colon.

Why correct: Ascending and descending colon usually become secondarily retroperitoneal as mesenteries fuse with posterior wall.

Why the other options are incorrect:

A. Jejunum: Has mobile mesentery and is intraperitoneal.

B. Transverse colon: Has transverse mesocolon and is usually intraperitoneal.

C. Sigmoid colon: Has sigmoid mesocolon and remains mobile intraperitoneal.

E. Caecum exclusively: Caecal peritoneal coverings vary, and not the canonical paired secondarily retroperitoneal segments.

Exam pearl: Ascending and descending colon are generally secondarily retroperitoneal.

Examiner trap: The duodenum is mostly retroperitoneal except proximal first portion.

Viva extension — What retroperitoneal structure is at risk in colonic mobilisation? Answer: Ureter.

Question 40 of 40 • Midgut–hindgut junction

Q40. Which portion of colon is near the developmental arterial transition between SMA and IMA supply?

A. CaecumB. Ascending colonC. Sigmoid colonD. Rectum below pectinate lineE. Junction of proximal two-thirds and distal third of transverse colon

View detailed explanation, examiner trap and viva

Correct answer: E. Junction of proximal two-thirds and distal third of transverse colon.

Why correct: Midgut conventionally includes proximal two-thirds transverse colon, while distal third belongs to hindgut.

Why the other options are incorrect:

A. Caecum: Clearly a midgut structure with ileocolic supply.

B. Ascending colon: Midgut territory supplied by SMA.

C. Sigmoid colon: Hindgut territory generally supplied by IMA.

D. Rectum below pectinate line: Not the embryological transverse-colon transition.

Exam pearl: The splenic flexure is a clinical watershed near SMA–IMA territories.

Examiner trap: Developmental border and exact vascular watershed are related but not identical fixed lines.

Viva extension — Which arteries form marginal collateral along colon? Answer: Marginal artery of Drummond.

Frequently asked questions

Are these official MRCS examination questions?

No. They are original syllabus-aligned educational SBAs informed by recurrent themes in uploaded recall collections. They are not the confidential content of an official MRCS examination.

Where should a chest drain pass relative to rib margins?

The main intercostal VAN bundle runs at inferior border of rib above; insertion just above upper edge of rib below reduces risk to main bundle, with careful site selection and procedure technique still necessary.

What is the key hysterectomy ureter relationship?

The ureter passes inferior to uterine artery near the cervix: water under the bridge.

How do I remember Pringle manoeuvre?

Compressing hepatoduodenal ligament temporarily reduces hepatic arterial and portal venous inflow, not hepatic venous outflow.

What does local progress mean?

Saved in current browser using localStorage. It will not sync to your other devices and might be lost if website data are cleared.

References and related MRCS lessons

Source-based clinical anatomy should be interpreted with patient-specific context. Recall papers have been used for topic prioritisation only; no inherited answer has been declared independently medically verified by default.

1. Official MRCS examination candidate guidance — MRCS syllabus and format.
2. TeachMeAnatomy: Thoracic wall vasculature — Rib bundle and chest-drain anatomical safety.
3. TeachMeAnatomy: Pelvic arteries — Uterine artery and ureter relationships.
4. TeachMeAnatomy: Pelvic ureters — Pelvic ureteric course and surgical risk.
5. TeachMeAnatomy: Pudendal nerve — Pudendal route, block and innervation.
6. TeachMeAnatomy: Peritoneal cavity — Greater and lesser sacs.
7. TeachMeAnatomy: Hepatocystic (Calot) triangle — Cystic duct, common hepatic duct and liver surface.
8. TeachMeAnatomy: Hepatic portal venous drainage — Portal vein and tributaries.
9. TeachMeAnatomy: Liver — Hepatoduodenal ligament and liver surfaces.

Continue your MRCS preparation

Article 01
Start MRCS HereArticle 02
Complete SyllabusArticle 03
Books and ResourcesArticle 04
12-Week Study PlanArticle 05
SBA Question StrategyArticle 06
Preparation MistakesArticle 07
Surgical Anatomy OverviewArticle 08
Upper Limb AnatomyArticle 09
Inguinal & Abdominal WallArticle 10
Head & Neck AnatomyArticle 11
Cardiorespiratory PhysiologyArticle 12
Renal & Acid-BaseArticle 13
GI Endocrine NeurophysiologyArticle 14
Lower Limb Surgical Anatomy

Previous lesson: Article 14 — Lower Limb Surgical Anatomy

Next planned lesson: Article 16 — Surgical Pathology and Wound Healing. The next link will be added only after its real published URL is known.

Last editorial update 16 October 2026. For education, not patient-specific management advice.