Unit 12 Veins & Lymphatics — Question Bank

Score — click each question to reveal the answer

The portal vein is formed by the union of the superior mesenteric vein and splenic vein. Where does this union occur?
Unit 12 Slide · Gray's 4e

A. Behind the neck of the pancreas

B. In front of the head of pancreas

C. At the porta hepatis

D. Behind the body of the pancreas at L3

✓ Answer: A — Behind the neck of the pancreas

The portal vein is formed by the union of the superior mesenteric vein (SMV) and the splenic vein, immediately behind the neck of the pancreas at approximately the level of L1–L2. It then runs upward and to the right, posterior to the duodenum and bile duct, to reach the porta hepatis.

⚠ Traps: A = the head of the pancreas is to the right of the neck; the portal vein forms behind the neck. C = the porta hepatis is where the portal vein enters the liver (its destination, not where it forms). D = L3 is too low; L1–L2 is correct.

What is the functional significance of the hepatic portal vein?
Unit 12 Slide · Gray's 4e

A. It carries oxygenated blood from the lungs to the liver

B. It carries nutrient-rich blood from the GI tract and spleen to the liver before systemic circulation

C. It drains deoxygenated blood from the liver directly to the IVC

D. It carries lymph-rich fluid from the mesentery to the liver

✓ Answer: B

The portal vein is a venous trunk between two capillary beds (unique property). It collects nutrient-rich, deoxygenated blood from the entire GI tract (stomach to upper rectum), spleen, and pancreas and delivers it to the hepatic sinusoids for first-pass metabolism before blood enters the systemic circulation via the hepatic veins.

⚠ The liver has a dual blood supply: ~75% portal vein (nutrient-rich, low O&sub2;) + ~25% hepatic artery (oxygenated). The portal vein carries no lymph and is not oxygenated.

The great saphenous vein is described as the longest vein in the body. Which of the following correctly describes its course?
Unit 12 Slide · Gray's 4e

A. Begins behind the lateral malleolus; drains into the popliteal vein

B. Begins at the medial malleolus; runs posteriorly; drains into the popliteal vein

C. Begins from the dorsal venous arch; passes in front of the medial malleolus; ascends along the medial leg and thigh; drains into the femoral vein

D. Begins from the plantar venous arch; passes posteriorly; drains into the external iliac vein directly

✓ Answer: C

The great saphenous vein begins from the dorsal venous arch of the foot, passes anterior to the medial malleolus, ascends along the medial aspect of the leg and thigh, and drains into the femoral vein through the saphenous opening (cribriform fascia) in the femoral triangle. It is the longest vein in the body and its tributaries include superficial epigastric, superficial iliac circumflex, and external pudendal veins.

⚠ A describes the small saphenous vein (behind lateral malleolus → popliteal vein). C is partially correct regarding the medial side but wrong about the posterior course and drainage. The great saphenous drains into the femoral, NOT the external iliac directly.

The small saphenous vein:
Unit 12 Slide

A. Begins from the dorsal venous arch; runs anterior to the medial malleolus; drains into the femoral vein

B. Runs along the lateral aspect of the leg and drains into the external iliac vein

C. Drains directly into the great saphenous vein above the knee

D. Begins from the dorsal venous arch; runs behind the lateral malleolus; ascends the posterior calf; drains into the popliteal vein

✓ Answer: D

The small (short) saphenous vein commences from the dorsal venous arch of the foot, passes posterior to the lateral malleolus, ascends along the posterior aspect of the calf, and drains into the popliteal vein in the popliteal fossa. It is the shorter of the two main superficial leg veins and is a common site for varicose veins of the posterior calf.

⚠ A describes the great saphenous vein. The key distinguishing features: great = medial malleolus, femoral vein; small = lateral malleolus, popliteal vein.

The median cubital vein is of major clinical importance because it is the preferred site for venepuncture. It connects which two superficial veins of the upper limb?
Unit 12 Slide · Gray's 4e

A. Cephalic vein and basilic vein

B. Axillary vein and brachial vein

C. Radial vein and ulnar vein

D. Cephalic vein and axillary vein

✓ Answer: A — Cephalic and basilic veins

The median cubital vein lies in the cubital fossa and obliquely connects the cephalic vein (lateral side) to the basilic vein (medial side). It is the site of choice for venepuncture and IV cannulation because it is large, relatively fixed, and superficial. The underlying brachial artery is separated from it by the bicipital aponeurosis (lacertus fibrosus), providing a degree of protection.

⚠ A and C are deep veins. D is wrong — the cephalic and axillary do not connect via the median cubital. The median cubital specifically links cephalic to basilic.

The cephalic vein of the upper limb drains into:
Unit 12 Slide · Gray's 4e

A. Brachial vein at the elbow

B. Axillary vein in the deltopectoral groove

C. Subclavian vein at the clavicle

D. Internal jugular vein at the root of the neck

✓ Answer: B — Axillary vein

The cephalic vein runs along the lateral (radial) side of the arm in the deltopectoral groove between the deltoid and pectoralis major, then pierces the clavipectoral fascia to drain into the axillary vein. It receives the accessory cephalic vein from the forearm. It is often used for central venous access (PICC lines placed via cubital fossa reach the axillary → subclavian → SVC).

⚠ B is a common error — the cephalic empties into the axillary, not directly into the subclavian. The subclavian is the continuation of the axillary vein after the lateral border of the 1st rib.

The basilic vein runs along the medial side of the upper limb. At what point does it become the axillary vein?
Unit 12 Slide · Gray's 4e

A. It joins the brachial vein at the elbow, forming the axillary vein

B. It joins the cephalic vein in the axilla to form the axillary vein

C. It joins the two brachial veins at the lower border of teres major to form the axillary vein

D. It directly becomes the subclavian vein at the clavicle

✓ Answer: C — Joins brachial veins at lower border of teres major

The basilic vein ascends the medial aspect of the arm, pierces the deep fascia at about the middle of the arm, and then joins the paired brachial veins at the lower border of teres major to form the axillary vein. The axillary vein continues to the lateral border of the 1st rib where it becomes the subclavian vein.

⚠ A is partially right about the brachial component but wrong about the elbow. The basilic only joins the brachial veins at the lower border of teres major (upper arm), not at the elbow.

The thoracic duct drains lymph from all of the following EXCEPT:
Unit 12 Slide · Gray's 4e

A. Both lower limbs and pelvis

B. Abdominal cavity

C. Left upper limb and left thorax

D. Right side of head and neck

✓ Answer: D — Right head and neck is drained by the RIGHT lymphatic duct

The thoracic duct drains approximately three-quarters of the body — specifically: both lower limbs, pelvis, abdomen, left thorax, left upper limb, and left head and neck. The upper right quadrant (right head/neck + right arm + right thorax) drains via the right lymphatic duct into the right venous angle. The thoracic duct terminates at the left venous angle (junction of left internal jugular and left subclavian veins).

⚠ Mnemonic: “Everything EXCEPT the upper right quadrant” goes through the thoracic duct. In thoracic duct injury (e.g. oesophagectomy), chylothorax forms on the left (or right if injury is low).

Which region of the body is drained exclusively by the right lymphatic duct?
Unit 12 Slide

A. Right head and neck, right upper limb, and right thorax

B. Right lower limb and right pelvis

C. Right half of the abdomen

D. Entire right side of the body

✓ Answer: A — Upper right quadrant

The right lymphatic duct is formed by the union of the right jugular trunk + right subclavian trunk + right bronchomediastinal trunk. It drains the right half of the head and neck, the right upper limb, and the right thorax — together called the “upper right quadrant.” It empties into the right venous angle.

⚠ A and B are wrong — the lower limbs and abdomen both drain via the thoracic duct. D is wrong — the right lower limb is not included. Only the upper right quadrant is the right lymphatic duct's territory.

Q10

In portal hypertension, oesophageal varices result from engorgement of which portosystemic anastomosis?
Unit 12 Slide · Gray's 4e

A. Paraumbilical veins ↔ epigastric veins at the umbilicus

B. Left gastric vein ↔ oesophageal veins ↔ azygos vein at the lower oesophagus

C. Superior rectal vein ↔ middle and inferior rectal veins at the rectum

D. Colic veins ↔ retroperitoneal lumbar veins

✓ Answer: B — Lower oesophagus: left gastric ↔ azygos

The portosystemic anastomosis at the lower oesophagus: portal system → left gastric (coronary) vein → oesophageal submucosal venous plexus ↔ systemic system → oesophageal veins → azygos vein → SVC. In portal hypertension, blood is shunted retrogradely, dilating the submucosal oesophageal veins into varices. Risk of rupture → massive haematemesis (mortality ~30% per bleed).

⚠ A = caput medusae (umbilicus); C = rectal varices; D = retroperitoneal (Retzius). Oesophageal varices are the most clinically dangerous portosystemic site.

Q11

The portosystemic anastomosis at the rectum connects:
Unit 12 Slide · Gray's 4e

A. Inferior mesenteric vein (portal) ↔ internal iliac vein (systemic)

B. Paraumbilical veins (portal) ↔ epigastric veins (systemic)

C. Superior rectal vein (portal) ↔ middle and inferior rectal veins (systemic)

D. Left gastric vein (portal) ↔ azygos vein (systemic)

✓ Answer: C

Rectal portosystemic anastomosis: portal system → superior rectal vein (tributary of inferior mesenteric vein → portal) ↔ systemic → middle rectal veins (from internal iliac) and inferior rectal veins (from internal pudendal → internal iliac → IVC) via the rectal venous plexus. Portal hypertension engorgement here causes rectal varices (distinct from haemorrhoids, which are cushions of arteriovenous tissue).

⚠ C = umbilical site; D = oesophageal site. A is partially correct in naming vessels but misses the key connection through the superior rectal vein specifically.

Q12

Caput medusae — dilated veins radiating from the umbilicus in portal hypertension — results from engorgement of which portosystemic anastomosis?
Unit 12 Slide · Gray's 4e

A. Superior rectal vein ↔ middle/inferior rectal veins

B. Left gastric vein ↔ oesophageal veins

C. Splenic vein ↔ left renal vein

D. Paraumbilical veins ↔ superior/inferior epigastric veins at the umbilicus

✓ Answer: D — Umbilical / periumbilical site

The umbilical portosystemic anastomosis: portal system → paraumbilical veins (run in the falciform ligament alongside the ligamentum teres, connecting to the left branch of the portal vein) ↔ systemic system → superior epigastric (to internal thoracic → SVC) and inferior epigastric (to external iliac → IVC) veins. Engorgement produces caput medusae (flow direction = away from umbilicus, distinguishing it from IVC obstruction where flow is upward on the flanks).

⚠ A = rectum; B = lower oesophagus; D = spontaneous splenorenal shunt (not an anatomical portosystemic anastomosis listed in the classic description). Caput medusae is pathognomonic of portal hypertension.

Q13

The superior vena cava (SVC) is formed by the junction of the left and right brachiocephalic veins. At what level does this occur?
Unit 12 Slide · Gray's 4e

A. Behind the lower border of the 1st right costal cartilage

B. Behind the upper border of the 1st right costal cartilage

C. At the level of the 2nd right intercostal space

D. Behind the manubriosternal junction (angle of Louis)

✓ Answer: A — Lower border of 1st right costal cartilage

The SVC is formed by the union of the left and right brachiocephalic veins behind the lower border of the 1st right costal cartilage. It descends ~7 cm to open into the right atrium at the level of the 3rd right costal cartilage. The azygos vein arches over the root of the right lung to open into the SVC from behind at the level of T4 (angle of Louis level).

⚠ Slides specifically state “lower border of the first right costal cartilage.” The SVC also receives the azygos vein — a key tributary worth mentioning in any SVC essay.

Q14

The inferior vena cava (IVC) is formed at the level of L5. Where does it enter the thorax?
Unit 12 Slide · Gray's 4e

A. Through the aortic hiatus of the diaphragm at T12

B. Through the caval opening (foramen venae cavae) of the diaphragm at T8

C. Through the oesophageal hiatus at T10

D. Through the right crus of the diaphragm at T10

✓ Answer: B — Caval opening at T8

The IVC forms by junction of the two common iliac veins in front of the body of L5 (just to the right of the aortic bifurcation). It ascends on the right side of the aorta, passes through the caval opening (foramen venae cavae) of the central tendon of the diaphragm at T8, and immediately enters the right atrium. The right phrenic nerve also passes through this opening.

⚠ The three diaphragmatic openings mnemonic: T8 = IVC, T10 = Oesophagus + vagus nerves, T12 = Aorta + thoracic duct + azygos. T8 is the highest and most anterior.

Q15

Which statement about the hepatic veins is CORRECT?
Unit 12 Slide · Gray's 4e

A. The hepatic veins drain into the portal vein

B. There are four hepatic veins: right, left, middle, and inferior

C. The right, middle and left hepatic veins drain directly into the IVC

D. The hepatic veins carry nutrient-rich blood from the intestine to the liver

✓ Answer: C — Drain directly into the IVC

There are three main hepatic veins: right, middle, and left. They drain the liver sinusoids (receiving processed blood from both portal and hepatic arterial inputs) and open directly into the inferior vena cava just below the diaphragm at T8–T9. This is why hepatic veins are visceral tributaries of the IVC, not part of the portal system.

⚠ A is a critical error to avoid: hepatic veins drain out of the liver into the IVC; the portal vein brings blood into the liver. D describes the portal vein's function. B is wrong — three main veins, not four.

Q16

The azygos vein:
Unit 12 Slide · Gray's 4e

A. Runs on the left side of the vertebral column and drains into the SVC

B. Runs on the right side and drains directly into the right atrium

C. Commences at L5 and drains the anterior abdominal wall

D. Commences from the right ascending lumbar vein and drains into the SVC at approximately T4

✓ Answer: D

The azygos vein commences from the right ascending lumbar vein, enters the thorax through the aortic hiatus (or right crus of the diaphragm), runs on the right side of the vertebral column between the thoracic aorta and azygos vein, and arches over the root of the right lung to enter the SVC from behind at approximately T4 (level of the sternal angle). It drains the posterior thoracic wall (intercostal veins) and is part of the important collateral pathway if the SVC or IVC is obstructed.

⚠ A is the hemi-azygos (left side). C is wrong — the azygos drains into the SVC, not the right atrium directly. The azygos provides an important bypass collateral when the SVC or IVC is obstructed.

Q17

The hemi-azygos vein:
Unit 12 Slide

A. Begins as the continuation of the left ascending lumbar vein and drains into the azygos vein

B. Runs on the right side and drains into the SVC

C. Drains the right posterior intercostal spaces directly

D. Is formed by union of the left and right ascending lumbar veins

✓ Answer: A

The hemi-azygos vein begins as the continuation of the left ascending lumbar vein, runs on the left side of the vertebral column, and crosses the midline to drain into the azygos vein. The accessory hemi-azygos vein drains the upper left intercostal spaces and also joins the hemi-azygos. Together they represent the left-sided counterpart of the azygos system, draining the left posterior thoracic wall.

⚠ A describes the azygos (right side → SVC). The key distinction: azygos = right side, drains to SVC; hemi-azygos = left side, drains to azygos.

Q18

The cisterna chyli:
Unit 12 Slide · Gray's 4e

A. Is located at T4 and receives the right and left jugular trunks

B. Is a dilated sac at L1–L2 formed by joining of the intestinal trunk and right and left lumbar trunks; it is the origin of the thoracic duct

C. Drains directly into the left subclavian vein

D. Is located in the posterior mediastinum and receives lymph from the upper limbs

✓ Answer: B

The cisterna chyli is a dilated sac (lymphatic cistern) located in front of the L1–L2 vertebral bodies, to the right of the aorta. It is formed by the joining of the right lumbar trunk + left lumbar trunk + intestinal trunk. The thoracic duct begins here, enters the thorax through the aortic hiatus at T12, and ascends to the left venous angle. It is called “cisterna chyli” (chyle cistern) because it receives the fat-rich chyle from the intestinal trunk.

⚠ A describes the termination of the thoracic duct's tributaries (jugular trunks join just before it ends at the left venous angle). C is where the thoracic duct terminates, not where the cisterna chyli drains.

Q19

A patient develops sudden-onset calf pain, swelling, and warmth after a long-haul flight. Deep vein thrombosis (DVT) is diagnosed. What is the most feared immediate complication?
Unit 12 Slide · Gray's 4e

A. Varicose veins of the great saphenous territory

B. Portal hypertension from IVC obstruction

C. Pulmonary embolism (thrombus detaches and lodges in pulmonary arteries)

D. Caput medusae from retrograde portal flow

✓ Answer: C — Pulmonary embolism

DVT most commonly occurs in the deep veins of the lower limb (popliteal, femoral, iliac veins). Risk factors include immobility (Virchow's triad: stasis, endothelial damage, hypercoagulability). The most feared complication is pulmonary embolism (PE): a thrombus fragment detaches, travels via the IVC → right atrium → right ventricle → pulmonary arteries, causing acute obstruction. Massive PE can cause sudden death. Superficial veins (great saphenous) are the site of varicose veins, not DVT.

⚠ Varicose veins affect the great saphenous (superficial), not deep veins. Portal hypertension is unrelated to peripheral DVT. DVT → PE is a classic exam association.

Q20

A 58-year-old man presents with progressive facial swelling, arm oedema, and dilated veins over the anterior chest wall. CT shows a large mediastinal mass compressing the SVC. This is called SVC syndrome. Which of the following best explains the clinical signs?
Unit 12 Slide · Gray's 4e

A. Obstruction of the IVC causing lower limb oedema

B. Portal hypertension due to SVC compression reducing hepatic venous drainage

C. Lymphatic obstruction at the thoracic duct causing chylothorax

D. Obstruction of venous drainage from the head, neck, upper limbs, and thorax due to SVC compression; collateral flow via azygos and chest wall veins

✓ Answer: D — SVC compression, collateral flow via azygos/chest wall

SVC syndrome: the SVC is compressed (most commonly by a right-sided bronchogenic carcinoma or lymphoma in the right mediastinum). This obstructs venous drainage from the head, neck, upper limbs, and thorax (the SVC's drainage territory via the brachiocephalic veins). Clinical features: facial plethora and oedema, arm oedema, distended neck veins, dilated collateral veins on the anterior chest (collateral flow via azygos → IVC). The azygos arch is the principal collateral bypass.

⚠ A = IVC obstruction would cause lower limb / ascites signs, not upper body. C = SVC compression does not directly cause portal hypertension. D = chylothorax is a thoracic duct injury. The dilated chest veins in SVC syndrome flow downward (toward IVC) to bypass the blocked SVC.

D1 Portal Vein (Hepatic Portal Vein) +

A short venous trunk (~8 cm), unique in being a venous channel between two capillary beds (no venous valves). Formed by the union of the superior mesenteric vein and splenic vein behind the neck of the pancreas at L1–L2. Ascends in the free edge of the lesser omentum (hepatoduodenal ligament) posterior to the bile duct and hepatic artery proper. At the porta hepatis, it divides into right and left branches entering the liver. Tributaries include the left and right gastric veins, cystic vein, and paraumbilical veins. Clinical: portal hypertension (cirrhosis) → portosystemic anastomoses engorge → oesophageal varices, caput medusae, rectal varices.

Anatomy 12 Slide (Prof. Ping Zhang) · Gray's Anatomy 4e

D2 Cisterna Chyli +

A dilated sac (lymphatic cistern) lying in front of the bodies of L1–L2 vertebrae, to the right of the abdominal aorta. It is the origin of the thoracic duct, formed by the convergence of: (1) right lumbar lymphatic trunk, (2) left lumbar lymphatic trunk, and (3) intestinal trunk (carrying fat-rich chyle from the intestines). The name “cisterna chyli” reflects the milky, fat-rich lymph (chyle) it receives from intestinal absorption. The thoracic duct begins here, ascends through the aortic hiatus of the diaphragm at T12, and courses through the posterior mediastinum to reach the left venous angle.

Anatomy 12 Slide · Gray's Anatomy 4e

D3 Portosystemic (Porto-caval) Anastomosis +

A site where tributaries of the portal venous system communicate with tributaries of the systemic venous system (IVC or SVC). Normally these are small, low-pressure connections. In portal hypertension (portal pressure >10 mmHg), blood is forced retrogradely through these anastomoses, causing venous engorgement at each site. The five clinically recognised sites are:

1. Lower oesophagus: left gastric vein ↔ oesophageal veins ↔ azygos → SVC → oesophageal varices (most dangerous)
2. Rectum: superior rectal vein ↔ middle/inferior rectal veins ↔ IVC → rectal varices
3. Umbilicus: paraumbilical veins ↔ epigastric veins ↔ SVC + IVC → caput medusae
4. Retroperitoneum: colic veins ↔ lumbar/posterior abdominal wall veins ↔ IVC
5. Bare area of liver: portal tributaries ↔ inferior phrenic veins ↔ IVC

Anatomy 12 Slide · Gray's Anatomy 4e · Unit 12 Master Structure

D4 Great Saphenous Vein +

The longest vein in the body. Origin: the medial end of the dorsal venous arch of the foot. Course: passes anterior to the medial malleolus, ascends along the medial aspect of the leg and thigh, passes through the saphenous opening (cribriform fascia) in the femoral triangle, and drains into the femoral vein approximately 3–4 cm below the inguinal ligament. Tributaries at its termination (the “sapheno-femoral junction”): superficial epigastric vein, superficial iliac circumflex vein, superficial and deep external pudendal veins. Clinical: (1) Varicose veins (incompetent valves → tortuous dilatation); (2) Coronary artery bypass graft (CABG) conduit; (3) Saphenous cutdown access; (4) DVT prophylaxis education.

Anatomy 12 Slide · Gray's Anatomy 4e

D5 Thoracic Duct +

The principal lymphatic vessel of the body, draining approximately three-quarters of total body lymph. Origin: the cisterna chyli at L1–L2. Course: enters thorax through the aortic hiatus of the diaphragm at T12; ascends in the posterior mediastinum between the thoracic aorta (left) and azygos vein (right); at the level of T5 it inclines to the left; at the root of the neck it arches forward and laterally over the subclavian artery and drains into the left venous angle (junction of left internal jugular and left subclavian veins). Just before its termination it receives the left jugular trunk, left subclavian trunk, and left bronchomediastinal trunk. Drainage territory: both lower limbs, pelvis, abdomen, left thorax, left upper limb, left head and neck. Clinical: injury during oesophagectomy or left neck dissection → chylothorax or chyle fistula.

Anatomy 12 Slide · Gray's Anatomy 4e

D6 Caput Medusae +

The clinical sign of dilated, tortuous superficial veins radiating outward from the umbilicus in patients with severe portal hypertension (the name references Medusa's snake-hair). Caused by engorgement of the umbilical portosystemic anastomosis: portal hypertension → blood shunted retrogradely through the paraumbilical veins (running in the falciform ligament alongside the ligamentum teres hepatis) into the periumbilical venous network → these dilate visibly under the skin. Flow direction is away from the umbilicus in all directions, which clinically distinguishes caput medusae from IVC obstruction (where flow is upward on the flanks because blood bypasses the blocked IVC via chest wall veins). Caput medusae is pathognomonic of significant portal hypertension, most commonly from liver cirrhosis.

Anatomy 12 Slide · Gray's Anatomy 4e · Unit 12 Master Structure

Essay 1

Describe the portal venous system: formation, tributaries, the portosystemic anastomoses (name all five sites with the portal and systemic vessels at each), and the clinical consequences of portal hypertension.

10 marks

Formation

The portal vein is formed by the union of the superior mesenteric vein (SMV) and the splenic vein immediately behind the neck of the pancreas (L1–L2). It is a short trunk (~8 cm) with no venous valves — a unique characteristic. It ascends in the hepatoduodenal ligament (free edge of lesser omentum) behind the bile duct and hepatic artery proper, and at the porta hepatis divides into right and left branches to enter the liver sinusoids.

Tributaries

Superior mesenteric vein — drains small intestine, caecum, ascending and transverse colon
Splenic vein — receives inferior mesenteric vein (descending colon, sigmoid, upper rectum), left gastroepiploic, short gastric veins
Left gastric (coronary) vein — lesser curvature and lower oesophagus
Right gastric vein — lesser curvature
Cystic vein — gallbladder
Paraumbilical veins — run in falciform ligament alongside ligamentum teres

Portosystemic Anastomoses (all five sites)

1. Lower oesophagus: Left gastric vein (portal) ↔ oesophageal veins ↔ azygos vein (systemic → SVC). Clinical: oesophageal varices — most dangerous; rupture causes torrential haematemesis (mortality ~30% per bleed)
2. Rectum: Superior rectal vein (portal, via IMV) ↔ middle and inferior rectal veins (systemic, via internal iliac → IVC). Clinical: rectal varices
3. Umbilicus: Paraumbilical veins (portal, connect to left branch of portal vein) ↔ superior and inferior epigastric veins (systemic → SVC + IVC). Clinical: caput medusae
4. Retroperitoneum: Colic veins and other mesenteric tributaries (portal) ↔ retroperitoneal veins of Retzius (systemic → IVC). Clinical: usually asymptomatic; bleed risk during retroperitoneal surgery in portal hypertension
5. Bare area of liver: Portal vein tributaries in the bare area ↔ inferior phrenic and diaphragmatic veins (systemic → IVC). Clinical: minor pathway; less clinically significant

Clinical: Portal Hypertension

Defined as portal pressure >10 mmHg (normal 5–10 mmHg). Commonest cause: liver cirrhosis (increased intrahepatic resistance)
Signs: oesophageal varices (haematemesis), splenomegaly, ascites, caput medusae, rectal varices, jaundice
Management of varices: endoscopic banding, TIPS (transjugular intrahepatic portosystemic shunt), propranolol (non-selective β-blocker to reduce portal pressure)

Marking (10 marks): Portal vein formation (site + vessels) = 1 · Four tributaries named correctly = 1 · Oesophageal anastomosis with correct portal/systemic vessels + clinical = 2 · Rectal anastomosis with vessels = 1 · Umbilical anastomosis + caput medusae = 1 · Retroperitoneal anastomosis = 0.5 · Bare area anastomosis = 0.5 · Definition of portal hypertension + cause = 1 · Three clinical signs = 1 · One management option = 1

Essay 2

Describe the thoracic duct: its origin at the cisterna chyli, course through thorax and neck, tributaries just before termination, and its drainage territory. Compare with the right lymphatic duct.

8 marks

Origin: Cisterna Chyli

The thoracic duct begins at the cisterna chyli, a dilated sac in front of L1–L2 bodies, formed by the confluence of: (1) right lumbar trunk, (2) left lumbar trunk, (3) intestinal trunk (chyle-bearing from intestinal absorption).

Course

Abdominal segment: none; starts at cisterna chyli at L1–L2
Enter thorax: passes through aortic hiatus of the diaphragm at T12
Posterior mediastinum: ascends on the front of the vertebral column, between the thoracic aorta (left) and azygos vein (right)
At T5: inclines to the left side
Upper thorax + neck: ascends on the left side, arches laterally over the left subclavian artery at the root of the neck
Termination: descends to enter the left venous angle (junction of left internal jugular and left subclavian veins)

Tributaries Just Before Termination

Left jugular trunk (from left head and neck)
Left subclavian trunk (from left upper limb)
Left bronchomediastinal trunk (from left thorax and mediastinum)

Drainage Territory

The thoracic duct drains approximately three-quarters of total body lymph: both lower limbs + pelvis, abdomen, left thorax, left upper limb, and left head and neck. In summary: everything EXCEPT the upper right quadrant.

Comparison: Right Lymphatic Duct

Formed by: right jugular trunk + right subclavian trunk + right bronchomediastinal trunk
Drains: upper right quadrant only (right head/neck + right upper limb + right thorax)
Terminates at: right venous angle
Much shorter and smaller than the thoracic duct

Clinical: Thoracic Duct Injury

Injury during oesophagectomy, aortic surgery, or left neck dissection → chylothorax (milky fluid in pleural cavity, high triglycerides). Treatment: ligation of the thoracic duct or conservative management (fat-free diet, octreotide).

Marking (8 marks): Origin at cisterna chyli with correct level (L1–L2) and forming trunks (1.5) · Course: aortic hiatus T12 + posterior mediastinum + inclines left at T5 (1.5) · Termination: left venous angle (1) · Three pre-termination tributaries (1) · Drainage territory summary (1) · Right lymphatic duct comparison: territory + termination (1) · Clinical complication (1)

Essay 3

Describe the superficial veins of the upper limb: cephalic vein, basilic vein, and median cubital vein — including their origin, course, termination, and clinical significance for venepuncture.

8 marks

Dorsal Venous Rete (Starting Point)

The superficial veins of the upper limb arise from the dorsal venous rete (network) of the hand. Two main superficial trunks ascend from this: the cephalic (lateral) and basilic (medial).

Cephalic Vein

Origin: lateral end of the dorsal venous rete of the hand
Course: ascends on the radial (lateral) side of the forearm; crosses to the anterior forearm; runs in the lateral bicipital groove of the arm; ascends in the deltopectoral groove between deltoid and pectoralis major
Termination: pierces the clavipectoral fascia to drain into the axillary vein
Tributaries include the accessory cephalic vein

Basilic Vein

Origin: medial end of the dorsal venous rete
Course: ascends on the ulnar (medial) side of the forearm; at the elbow it lies medial to the biceps tendon; pierces the deep fascia midway up the arm
Termination: joins the two brachial veins at the lower border of teres major to form the axillary vein

Median Cubital Vein

Position: in the cubital fossa (anterior elbow)
Connection: obliquely connects the cephalic vein (lateral) to the basilic vein (medial)
A perforating vein communicates with the deep veins of the forearm through the bicipital aponeurosis

Clinical: Venepuncture

The median cubital vein is the preferred site for venepuncture and IV cannulation because: it is large, relatively fixed, superficial, and not usually overlying major nerves or the brachial artery
The bicipital aponeurosis (lacertus fibrosus) separates the median cubital from the underlying brachial artery, providing protection during blind needling
The basilic vein (medial cubital fossa) lies close to the medial cutaneous nerve of the forearm and the brachial artery — hence less preferred
PICC lines (peripherally inserted central catheters) are most commonly inserted via the basilic or cephalic vein, with the tip advanced to the SVC–right atrial junction

Marking (8 marks): Cephalic: origin + lateral course + axillary vein termination (1.5) · Basilic: medial origin + pierces deep fascia + axillary vein via brachial (1.5) · Median cubital: position + cephalic-basilic connection (1) · Preferred venepuncture site identification + reason (1.5) · Bicipital aponeurosis protection (1) · PICC line application (0.5) · Warning re: basilic + brachial artery proximity (1)

Essay 4

Describe the superficial veins of the lower limb: great saphenous vein and small saphenous vein. Include origin, course, tributaries, termination, and clinical importance including varicose veins.

8 marks

Dorsal Venous Arch

Both superficial veins of the lower limb arise from the dorsal venous arch of the foot.

Great Saphenous Vein (GSV)

Origin: medial end of the dorsal venous arch
Course: passes anterior to the medial malleolus → ascends along the medial aspect of the leg with the saphenous nerve → continues along the medial aspect of the thigh → passes through the saphenous opening (cribriform fascia) in the femoral triangle, approximately 3–4 cm inferolateral to the pubic tubercle
Termination: femoral vein at the saphenofemoral junction
Key tributaries at termination: superficial epigastric vein, superficial iliac circumflex vein, external pudendal veins (superficial and deep), superficial lateral and medial femoral veins
It is the longest vein in the body

Small Saphenous Vein (SSV)

Origin: lateral end of the dorsal venous arch
Course: passes posterior to the lateral malleolus → ascends along the posterior aspect of the calf with the sural nerve
Termination: popliteal vein in the popliteal fossa (it penetrates the deep fascia to reach the popliteal vein)

Clinical Importance

Varicose veins: Incompetent venous valves (especially at the saphenofemoral junction) allow reflux → raised venous pressure → tortuous dilatation of the GSV and its tributaries. Symptoms: aching, heaviness, skin changes. Complications: venous eczema, lipodermatosclerosis, venous ulceration (medial ankle = gaiter area). Treatment: compression stockings, endovenous ablation, foam sclerotherapy, saphenofemoral ligation (Trendelenburg procedure)
CABG conduit: The GSV is the most commonly used vein graft for coronary artery bypass surgery
Saphenous cutdown: Emergency venous access when peripheral veins collapse; the GSV is accessed anterior to the medial malleolus
DVT and PE: Deep veins (not saphenous) are the site of DVT; thrombus can propagate from deep calf veins proximally, risking pulmonary embolism

Marking (8 marks): GSV: origin (medial arch) + medial malleolus passage + medial leg/thigh course + femoral vein termination (2) · GSV tributaries at SFJ (1) · Longest vein stated (0.5) · SSV: origin (lateral arch) + posterior lateral malleolus + posterior calf + popliteal termination (2) · Varicose veins: mechanism + sites + one complication (1.5) · CABG / cutdown applications (1)

Essay 5

Describe the superior vena cava (SVC): formation, course, tributaries, and the azygos venous system. Explain the anatomy of SVC syndrome and the collateral pathways that develop.

8 marks

Formation

The SVC is formed by the union of the left and right brachiocephalic veins (innominate veins) behind the lower border of the 1st right costal cartilage. Each brachiocephalic vein is formed behind the sternoclavicular joint by the union of the internal jugular vein and subclavian vein of the same side. The angle of union is the venous angle, where the lymphatic ducts terminate.

Course and Termination

The SVC descends approximately 7 cm, lying to the right of the ascending aorta
It is covered anteriorly by the pericardium in its lower half
It opens into the right atrium at the level of the 3rd right costal cartilage

Key Tributary: Azygos Vein

The azygos vein arches over the root of the right lung to open into the posterior aspect of the SVC at approximately T4 (level of the sternal angle)
This is the most important tributary of the SVC

Azygos System

Azygos vein: commences from the right ascending lumbar vein; enters thorax through the aortic hiatus (or right crus); runs on the right side of the vertebral column; drains right posterior intercostal veins and hemi-azygos; arches over right lung root → SVC at T4
Hemi-azygos vein: commences from the left ascending lumbar vein; runs on the left side; crosses midline → drains into azygos vein; drains left lower posterior intercostal veins
Accessory hemi-azygos vein: drains upper left intercostal veins → hemi-azygos or directly to azygos
The azygos system provides a collateral bypass: if the IVC is obstructed, blood can drain up via the ascending lumbar veins → azygos → SVC; if the SVC is obstructed, blood drains down via azygos → IVC

SVC Syndrome

Cause: obstruction of the SVC, most commonly by a right-sided bronchogenic carcinoma, lymphoma, or mediastinal fibrosis
Anatomy of obstruction: the SVC lies in the right side of the superior mediastinum, closely related to the right main bronchus, paratracheal lymph nodes, and ascending aorta — all potential compressors
Clinical features (all from impaired drainage of the head, neck, upper limbs, and thorax): facial plethora and oedema, oedema of the upper limbs, distended non-pulsatile neck veins, dilated collateral veins on the anterior chest wall, headache, cyanosis, dyspnoea
Collateral pathways: Blood bypasses the blocked SVC via: (1) azygos vein → IVC (primary bypass); (2) internal thoracic → anterior abdominal wall veins → IVC; (3) superficial chest and back veins; (4) vertebral venous plexus. Flow in chest wall veins is downward (toward IVC), distinguishing it from IVC obstruction where flow is upward

Marking (8 marks): SVC formation (brachiocephalic veins, level, each BC vein = IJ + subclavian) (2) · SVC course and termination in right atrium (0.5) · Azygos as key tributary + level T4 (1) · Azygos system: azygos origin/right side/SVC + hemi-azygos/left side/azygos (1.5) · Collateral value of azygos stated (0.5) · SVC syndrome: cause + clinical features (1.5) · Collateral pathways including direction of flow (1)

Unit 12 — Veins & Lymphatics · Question Bank

Formation

Tributaries

Portosystemic Anastomoses (all five sites)

Clinical: Portal Hypertension

Origin: Cisterna Chyli

Course

Tributaries Just Before Termination

Drainage Territory

Comparison: Right Lymphatic Duct

Clinical: Thoracic Duct Injury

Dorsal Venous Rete (Starting Point)

Cephalic Vein

Basilic Vein

Median Cubital Vein

Clinical: Venepuncture

Dorsal Venous Arch

Great Saphenous Vein (GSV)

Small Saphenous Vein (SSV)

Clinical Importance

Formation

Course and Termination

Key Tributary: Azygos Vein

Azygos System

SVC Syndrome