Unit 06 Alimentary Glands & Respiratory System — Question Bank

Score — click each question to reveal the answer

Which of the following correctly states the THREE borders of Calot’s triangle (cystohepatic triangle)?
TMU Slide 6 — Gallbladder Triangle

A. Cystic duct, common hepatic duct, inferior surface of liver

B. Cystic duct, common bile duct, inferior surface of liver

C. Cystic duct, right hepatic duct, gallbladder

D. Common hepatic duct, right hepatic duct, liver hilum

✓ Answer: A — Cystic duct / common hepatic duct / inferior surface of liver

Calot’s triangle (gall-bladder triangle) boundaries as stated verbatim in the TMU Slide 6 text: cystic duct (inferior border), common hepatic duct (medial border), and inferior surface of the liver (superior border). The triangle contains the cystic artery, which arises from the right branch of the proper hepatic artery and is found here in ~62% of people. The cystic artery passes posterior (75%) or anterior (24%) to the common hepatic duct.

⚠ Trap: A substitutes “common bile duct” for “common hepatic duct” — the medial border is the common hepatic duct (above the cystic-common hepatic junction), not the common bile duct (which forms after they join). This distinction matters in cholecystectomy.

The Couinaud segmental classification divides the liver into how many functional segments, based on the distribution of portal vein branches and hepatic veins?
Gray’s Anatomy 4e p.280

A. Four segments (based on the four lobes)

B. Eight segments (I–VIII)

C. Six segments (three per side)

D. Ten segments (mirroring bronchopulmonary)

✓ Answer: B — Eight segments (Couinaud I–VIII)

Couinaud (1957) divided the liver into 8 functional segments (I–VIII), each with its own portal branch, hepatic artery branch, and bile duct — making each an independent surgical unit. The three hepatic veins (right, middle, left) run in the inter-segmental planes between them. Segment I = caudate lobe (has independent hepatic venous drainage directly to IVC — crucial in Budd-Chiari syndrome). Segments II–IV = left lobe; V–VIII = right lobe.

⚠ The older 4-lobe description (right/left/quadrate/caudate) is morphological, not functional. Couinaud segments are defined by vascular/biliary supply — a segment can be resected without devascularising adjacent segments.

Centrilobular necrosis of the liver (as seen in paracetamol [acetaminophen] overdose) primarily affects which zone of the hepatic acinus?
Gray’s Anatomy 4e p.276

A. Zone 1 — periportal zone (richest O² and nutrients)

B. Zone 2 — mid-zone

C. Zone 3 — centrilobular zone (lowest O², highest drug-metabolising enzymes)

D. All zones equally (panlobular necrosis)

✓ Answer: C — Zone 3 (centrilobular)

Rappaport’s hepatic acinus has three zones based on distance from the portal triad. Zone 3 (centrilobular, around the central/terminal hepatic vein) has the lowest oxygen tension and the highest concentration of CYP450 enzymes (especially CYP2E1) that convert paracetamol to the toxic metabolite NAPQI. This makes zone 3 most vulnerable to centrilobular necrosis in paracetamol overdose. Zone 1 = periportal (first to receive O² + nutrients; damaged by ischaemia in right heart failure in a different pattern). Zone 2 = mid-acinar.

⚠ Mnemonic: Zone 1 = first to receive, last to die (ischaemia hits Z3 first). Zone 3 = last to receive O², first to die in drug toxicity. Yellow fever causes mid-zonal (Zone 2) necrosis — rare exam distractor.

A 3-year-old child inhales a peanut. On bronchoscopy, in which airway is the foreign body most likely found, and why?
TMU Slide 6 — Section 5 Bronchi; Case Analysis

A. Left main bronchus — it is longer and more muscular

B. Right lower lobar bronchus — foreign bodies always go to the lower lobe

C. Trachea at carina — the widest point traps the object

D. Right main bronchus — shorter, wider, more vertical, carina deviated left

✓ Answer: D — Right main bronchus

The TMU slide states verbatim: “Foreign objects from the trachea usually pass to the right bronchus. The right principal bronchus is shorter (2–3 cm), wider in diameter and more vertical in position. The carina of trachea is more to the left.” These three anatomical features together explain why aspirated material preferentially enters the right. In children the angle difference is even more pronounced. Below the carina, the object typically lodges in the right lower lobe bronchus (most vertical path).

⚠ Left bronchus: 4–5 cm long, finer, and oblique (passes under the aortic arch and in front of the descending aorta). Right bronchus: 2–3 cm, wider, near-vertical. The case analysis in the slide confirms answer: right lower lobar bronchus.

Which lobe of the liver is the most common site of a pyogenic (bacterial) liver abscess, and what anatomical reason explains this?
Gray’s Anatomy 4e p.279

A. Right lobe — it receives ~70% of portal blood flow

B. Left lobe — it is more superficial

C. Caudate lobe — it drains directly to the IVC

D. Quadrate lobe — it receives direct biliary drainage

✓ Answer: A — Right lobe

The right lobe is by far the most common site of pyogenic liver abscesses (up to 75% of cases). The anatomical reason: the right branch of the portal vein is shorter, wider, and more direct, receiving the bulk (~70%) of portal flow — including any bacteria seeded from appendicitis, diverticulitis, or bowel infection. Amoebic abscesses (Entamoeba histolytica) also favour the right lobe (posterior segment, near the right dome) for the same reason.

⚠ Left lobe abscesses are less common but associated with peptic ulcer disease or biliary causes. The caudate lobe (segment I) has independent drainage directly to IVC — relevant in Budd-Chiari syndrome, not abscesses.

Regarding the dual blood supply of the liver, which statement is CORRECT?
Gray’s Anatomy 4e p.279; TMU Slide 6 — Porta Hepatis

A. Hepatic artery proper supplies 75% of blood; portal vein supplies 25%

B. Portal vein supplies 75% of blood volume and ~50% of oxygen; hepatic artery supplies 25% of volume but ~50% of oxygen

C. Both vessels supply equal volumes of oxygenated blood

D. Hepatic veins carry oxygenated blood to the liver from the IVC

✓ Answer: B — Portal vein 75% volume / 50% O²; hepatic artery 25% volume / 50% O²

The liver has a dual blood supply via the porta hepatis. The portal vein delivers ~75% of the total hepatic blood volume — nutrient-rich but relatively deoxygenated blood from the GI tract. Despite only 25% of volume, the hepatic artery proper delivers ~50% of the liver’s oxygen because it carries fully oxygenated arterial blood. Both vessels enter at the porta hepatis along with the bile ducts. Venous drainage is via the hepatic veins (right, middle, left) → IVC.

⚠ Hepatic veins DRAIN the liver into the IVC — they carry deoxygenated blood OUT (option D is wrong). Hepatic artery supplies 25% blood volume but crucial for biliary epithelium oxygen. Portal vein occlusion alone is usually tolerated; combined with hepatic artery ischaemia it is fatal.

The fundus of the gallbladder projects onto the anterior abdominal wall at the surface marking known as:
TMU Slide 6 — Gallbladder Fundus; 2022 Review Slide 8

A. The mid-point of the right costal arch at the anterior axillary line

B. 5 cm below the xiphoid process in the midline

C. Tip of the 9th costal cartilage — where the lateral border of rectus abdominis meets the costal arch

D. McBurney’s point on the right side

✓ Answer: C — Tip of 9th costal cartilage / lateral border of rectus abdominis

The TMU slide states: “The body surface projection of the fundus of the gallbladder: lies behind the point where the lateral edge of the right rectus abdominis crosses the costal arch.” This corresponds to the tip of the 9th costal cartilage at the lateral border of rectus abdominis. Clinically this is the site of Murphy’s sign (positive in acute cholecystitis — press here on inspiration, patient catches breath).

⚠ Murphy’s sign: examiner places thumb below the right costal margin at this point; patient is asked to breathe in deeply; if the inflamed gallbladder descends onto the thumb → sharp pain + inspiratory arrest. Positive in acute cholecystitis.

The three constrictions of the oesophagus and their vertebral levels (from above down) are, in order:
2020 Past Paper Essay Q7; 2022 Review Slide 7; ANATOMY_MASTER 5.2

A. C4 (pharyngeal), T5 (aortic), T12 (diaphragmatic)

B. C5 (cricopharyngeal), T3 (aortic), T8 (diaphragmatic)

C. C7 (upper), T5 (middle), T11 (lower oesophageal sphincter)

D. C6 (cricopharyngeal), T4/T5 (aortic/bronchial), T10 (diaphragmatic)

✓ Answer: D — C6 / T4–T5 / T10

Three constrictions (mnemonic 15–25–40 cm from upper incisors): (1) Cricopharyngeal: at C6, 15 cm — where cricopharyngeus joins the oesophagus; narrowest point, commonest site of foreign body impaction; (2) Aortic/bronchial: at T4/T5, 25 cm — crossed by the left main bronchus anteriorly (and aortic arch superiorly); (3) Diaphragmatic: at T10, 40 cm — oesophageal hiatus of diaphragm; site of lower oesophageal sphincter; hiatus hernia occurs here.

⚠ The GOJ (gastro-oesophageal junction / cardiac orifice) is at T11, ~45 cm from incisors — this is NOT one of the three anatomical constrictions. NGT tip placement is confirmed at ~50 cm (well within stomach).

The right lung has how many lobes and how many bronchopulmonary segments?
TMU Slide 6 — Section 6 Lungs; ANATOMY_MASTER 6.5.4

A. 3 lobes, 10 segments

B. 2 lobes, 8 segments

C. 3 lobes, 8 segments

D. 2 lobes, 10 segments

✓ Answer: A — 3 lobes, 10 segments

The TMU slide states: “The right lung is divided into superior, middle and inferior lobes with a horizontal fissure and an oblique fissure. Each lung has ten segments.” Right lung: 3 lobes (upper/middle/lower) separated by oblique fissure + horizontal fissure, with 10 bronchopulmonary segments. Left lung: 2 lobes (upper/lower) separated by oblique fissure only, with 8–10 segments (lingula = homologue of right middle lobe).

⚠ Fissure count: right lung has TWO fissures (oblique + horizontal); left lung has ONE fissure (oblique only). The horizontal (minor) fissure separates the upper lobe from the middle lobe on the right. Left lung has no middle lobe — the lingula is part of the left upper lobe.

Q10

Pleural fluid (effusion) accumulates first in which part of the pleural cavity?
TMU Slide 6 — Section 7 Pleura; 2022 Review Slide 10

A. Cupula (dome) of pleura above the clavicle

B. Costodiaphragmatic recess (costophrenic recess)

C. Mediastinal pleural cavity adjacent to the heart

D. Pulmonary ligament inferiorly

✓ Answer: B — Costodiaphragmatic recess

The TMU slide states verbatim: “The costal and diaphragmatic pleurae are in contact with each other to form the costodiaphragmatic recess. It is the lowest portion of the pleural cavity.” Free fluid therefore accumulates here first by gravity. On chest X-ray, blunting of the costophrenic angle is the earliest sign of a pleural effusion (~200 mL needed to blunt on PA CXR, but only ~50 mL on lateral). Diagnostic / therapeutic thoracocentesis is inserted in this recess (typically 8th–9th intercostal space, posterior axillary line).

⚠ Projection of the inferior pleural margin is 2 ribs lower than the inferior lung margin: lung ends at 6/8/T10 (MCL/midaxillary/posterior); pleural reflection ends at 8/10/T12. The recess between these lines is the costodiaphragmatic recess.

Q11

The thyroid cartilage is clinically significant because:
TMU Slide 6 — Section 3 Larynx; ANATOMY_MASTER 6.5.2

A. It is the only complete ring in the respiratory tract

B. It forms the posterior wall of the larynx

C. Its anterior fusion forms the laryngeal prominence (Adam’s apple), more visible in males

D. It articulates with the arytenoid cartilages directly

✓ Answer: C — Forms the laryngeal prominence (Adam’s apple)

The TMU slide describes the thyroid cartilage: “It is the largest of the laryngeal cartilages. It comprises 2 laminae which are fused in front. Laryngeal prominence = median elevation at the fused part.” This is the Adam’s apple, more prominent in males due to a smaller fusion angle (~90° in males vs 120° in females). It forms the anterior and lateral walls of the larynx. The superior thyroid notch is above the fusion.

⚠ A describes the CRICOID cartilage (only complete ring). C describes the cricoid cartilage (posterior wall). D = the arytenoids articulate with the LAMINA of the cricoid, not the thyroid. The thyroid inferior cornu articulates with the cricoid at the cricothyroid joint.

Q12

Which laryngeal cartilage is the ONLY complete ring in the entire respiratory tract, and what is its significance?
TMU Slide 6 — Cricoid Cartilage; ANATOMY_MASTER 6.5.2

A. Thyroid cartilage — largest, forms Adam’s apple

B. Epiglottic cartilage — leaf-shaped, protects airway during swallowing

C. Arytenoid cartilages (paired) — control vocal fold movement

D. Cricoid cartilage — complete ring, forms posterior laryngeal wall

✓ Answer: D — Cricoid cartilage

The TMU slide states verbatim: “Cricoid cartilage is the only complete cartilage in the respiratory tract. It comprises a lamina of cricoid cartilage behind, a narrow arch of the cricoid cartilage in front.” It forms the posterior wall of the larynx. Its lamina articulates with the arytenoids (cricoarytenoid joint). Its lateral surface articulates with the inferior cornu of the thyroid (cricothyroid joint). All other respiratory tract cartilages (tracheal rings and thyroid cartilage) are incomplete (C-shaped), open posteriorly to allow oesophageal expansion during swallowing.

⚠ Cricothyroid membrane = space between thyroid and cricoid cartilages. This is the site of emergency cricothyrotomy (airway access when intubation fails). Landmark: feel thyroid notch → step down to the soft cricothyroid membrane → incise here. The cricoid ring prevents complete collapse.

Q13

The head of the pancreas sits in the concavity (C-loop) of which structure?
TMU Slide 6 — Section 9 Pancreas; ANATOMY_MASTER 6.3

A. Duodenum (C-shaped curve of duodenum)

B. Stomach (gastric antrum)

C. Transverse colon

D. Ascending colon at hepatic flexure

✓ Answer: A — Duodenum (C-loop)

The TMU slide states: “The head is curved by duodenum, tail reaches the hilum of the spleen.” The pancreatic head sits snugly in the concavity of the C-shaped duodenum (D1–D3). The uncinate process projects behind the superior mesenteric vessels. The main pancreatic duct (of Wirsung) joins the common bile duct to form the hepatopancreatic ampulla, which opens at the major duodenal papilla on the posteromedial wall of D2.

⚠ Clinical consequence: carcinoma of the head of the pancreas compresses the common bile duct → obstructive (painless) jaundice (Courvoisier’s sign: palpable non-tender gallbladder + jaundice). It also compresses D2 → obstructive vomiting. The pancreatic tail reaches the splenic hilum.

Q14

The major duodenal papilla (ampulla of Vater) opens on the posteromedial wall of which part of the duodenum?
TMU Slide 6 — Common Bile Duct; ANATOMY_MASTER 5.4.1

A. D1 — superior (1st) part

B. D2 — descending (2nd) part

C. D3 — horizontal (3rd) part

D. D4 — ascending (4th) part

✓ Answer: B — D2 (descending part)

The TMU slide states: “The [common bile duct] united with the pancreatic duct to form the hepatopancreatic ampulla. The ampulla opens into the descending part of the duodenum on the summit of the major duodenal papilla.” The major duodenal papilla is on the posteromedial wall of D2 at approximately L2. The minor duodenal papilla (accessory pancreatic duct) is ~2 cm above it. The sphincter of Oddi (sphincter of hepatopancreatic ampulla) controls bile and pancreatic juice release.

⚠ D1 = mobile, no papilla; D2 = papilla of Vater (posteromedial wall, retroperitoneal, in C of pancreatic head); D3 = crossed by SMA/SMV anteriorly (SMA syndrome). Obstruction at D2 level (gallstone impaction) causes bilious pancreatitis.

Q15

The parotid duct (Stensen’s duct) opens into the oral cavity opposite which tooth?
Gray’s Anatomy 4e p.850; 2022 Review Slide 6 — Salivary Glands

A. Upper first molar (opposite the 1st upper molar)

B. Lower first molar (opens on floor of mouth)

C. Upper second molar (opposite the 2nd upper molar)

D. Lower second molar (opens on sublingual caruncle)

✓ Answer: C — Upper second molar

The parotid duct (Stensen’s duct) exits the parotid gland on the lateral face, runs forward over masseter, pierces buccinator, and opens onto the mucous membrane of the cheek opposite the crown of the upper second molar tooth (2nd maxillary molar). The 2022 Review (Slide 6) asks: “Where do their ducts open?” as a required answer for salivary gland anatomy. This is the standard teaching point verified in Gray’s Anatomy for Students.

⚠ Three pairs of salivary glands and their duct openings: (1) Parotid (Stensen’s duct) → opposite upper 2nd molar; (2) Submandibular (Wharton’s duct) → sublingual caruncle, floor of mouth; (3) Sublingual (multiple ducts) → sublingual fold / caruncle. Parotid = CN IX parasympathetics via otic ganglion.

Q16

The submandibular gland duct (Wharton’s duct) opens at:
Gray’s Anatomy 4e p.854; 2022 Review Slide 6 — Salivary Glands

A. The cheek opposite the upper second molar

B. The hard palate posterolateral to the incisive foramen

C. The vestibule of the mouth, adjacent to the lower incisors

D. The sublingual caruncle on the floor of the mouth, lateral to the frenulum

✓ Answer: D — Sublingual caruncle, floor of mouth

Wharton’s duct (~5 cm long) runs forward from the submandibular gland, passes medial to the sublingual gland, and opens at the sublingual caruncle (small papilla on the floor of the mouth, lateral to the lingual frenulum) adjacent to the midline. The submandibular gland receives parasympathetic innervation from CN VII via the chorda tympani → submandibular ganglion. A calculus (stone) in Wharton’s duct causes swelling + pain under the jaw on eating (sialolithiasis), especially visible as a whitish lump on the floor of the mouth.

⚠ Memory hook: Stensen = Second molar (parotid); Wharton = floor of mouth at Wrist of tongue (frenulum). The submandibular gland wraps around the posterior edge of mylohyoid — superficial lobe is palpable below the mandible, deep lobe is above mylohyoid.

Q17

The trachea bifurcates into the right and left main bronchi at the carina. The vertebral level of bifurcation is:
TMU Slide 6 — Section 4 Trachea; ANATOMY_MASTER 6.5.3

A. T4/T5 — level of the sternal angle (angle of Louis)

B. T2/T3 — level of the jugular notch

C. T6/T7 — mid-thoracic

D. T1/T2 — thoracic inlet

✓ Answer: A — T4/T5 (sternal angle)

The TMU slide states: “The trachea extends from the lower border of the cricoid cartilage at the level of C6 to the level of the sternal angle (at the level of T4)” and “The trachea terminates at the level of T4 and is divided into the right and left principal bronchi.” The carina (internal sagittal ridge at the bifurcation) is seen on bronchoscopy and is a key landmark. The sternal angle (of Louis) is where rib 2 meets the sternum — a clinically palpable landmark at T4/T5.

⚠ The sternal angle at T4/T5 is a famous multi-purpose landmark: (1) carina/tracheal bifurcation, (2) aortic arch begins and ends, (3) superior mediastinum boundary, (4) ligamentum arteriosum (arterial ligament), (5) rib 2 (counting ribs from here), (6) nipple level (T4 dermatome). Mnemonic: 4Ts at T4.

Q18

The anterior mediastinum classically contains the “4 T’s.” Which list is correct?
Gray’s Anatomy 4e p.190; ANATOMY_MASTER 6.5 note

A. Trachea, Thymus, Thoracic duct, Tricuspid valve

B. Thymoma, Teratoma, Thyroid (retrosternal goitre), Terrible lymphoma

C. Trachea, Thoracic duct, Thyroid, Tracheomalacia

D. Thymoma, Thoracic aorta, Tricuspid mass, Trachea

✓ Answer: B — Thymoma / Teratoma / Thyroid / Terrible lymphoma

The anterior mediastinum (between sternum and pericardium) is the site of the classic 4 T’s: (1) Thymoma — most common anterior mediastinal mass in adults (>40 yr); associated with myasthenia gravis; (2) Teratoma (germ cell tumour) — most common in young adults; (3) Thyroid — retrosternal goitre descends through thoracic inlet; (4) Terrible lymphoma (Hodgkin’s and non-Hodgkin’s) — most common in young adults overall. The anterior mediastinum also normally contains the thymus (involuted in adults), internal thoracic vessels, lymph nodes, and fat.

⚠ Mediastinal divisions: Superior (above sternal angle) = aortic arch, SVC, trachea, oesophagus, thymus; Anterior (inferior, front of pericardium) = 4 Ts; Middle = heart/pericardium/phrenic nerves; Posterior = oesophagus, thoracic duct, descending aorta, azygos, sympathetic chain.

Q19

The bare area of the liver is significant because:
TMU Slide 6 — Diaphragmatic Surface; ANATOMY_MASTER 6.1

A. It is where the hepatic veins exit the liver before entering the IVC

B. It is the entry point for the hepatic portal vein and hepatic artery

C. It is bounded by the two layers of the coronary ligament and is devoid of peritoneum, lying directly on the diaphragm

D. It represents the H-shaped fissure on the visceral surface

✓ Answer: C — Between coronary ligament layers, no peritoneum, directly on diaphragm

The TMU slide states: “The diaphragmatic surface shows an area of the liver devoid of peritoneum known as bare area. The bare area is surrounded with the anterior and posterior coronary ligament.” The bare area is on the posterior part of the diaphragmatic surface, directly adherent to the diaphragm. There is no peritoneum here — hence “bare.” Clinical significance: (a) infection can spread between the liver and diaphragm via this extraperitoneal route (subphrenic abscess without peritoneal crossing); (b) a portosystemic anastomosis exists here (portal tributaries ↔ phrenic veins).

⚠ C = porta hepatis (on visceral/inferior surface). D = H-shaped fissure is on the visceral surface. A = hepatic veins exit near the IVC groove on the posterior diaphragmatic surface, adjacent to but distinct from the bare area boundary. The bare area contains the IVC groove (posteriorly) but is not the entry point for portal structures.

Q20

The splenic flexure (left colic flexure) of the colon is a watershed between which two arterial territories?
ANATOMY_MASTER 5.5.2; Gray’s Anatomy 4e p.315

A. Coeliac trunk and superior mesenteric artery (SMA)

B. Inferior mesenteric artery (IMA) and internal iliac artery

C. Superior mesenteric artery (SMA) and renal arteries

D. Superior mesenteric artery (SMA) and inferior mesenteric artery (IMA)

✓ Answer: D — SMA and IMA watershed at the splenic flexure

SMA territory: caecum → ascending colon → transverse colon (up to splenic flexure) via ileocolic, right colic, middle colic arteries. IMA territory: splenic flexure → descending colon → sigmoid → upper rectum via left colic, sigmoid, and superior rectal arteries. The splenic flexure is the watershed between these two systems. The marginal artery of Drummond connects them but is most tenuous here — making the splenic flexure the most vulnerable site for ischaemic colitis (e.g. after IMA ligation in aortic aneurysm repair).

⚠ Coeliac trunk (T12) supplies foregut (stomach, spleen, liver, duodenum D1, pancreas). SMA (L1) = midgut (D2 onward to splenic flexure). IMA (L3) = hindgut (splenic flexure to rectum). Rectum receives additional supply from internal iliac (middle/inferior rectal arteries) below IMA territory.

D1 Calot’s Triangle (Cystohepatic Triangle) +

A triangular space on the inferior surface of the liver bounded by: (1) Cystic duct (inferiorly), (2) Common hepatic duct (medially), (3) Inferior surface of the liver (superiorly). The triangle contains the cystic artery, which normally arises from the right branch of the proper hepatic artery and is found within the triangle in ~62% of individuals. The cystic artery may pass posterior (75%) or anterior (24%) to the common hepatic duct. Clinical significance: The cystic artery must be identified and ligated within Calot’s triangle during laparoscopic or open cholecystectomy. Failure to correctly identify the triangle or anomalous cystic artery anatomy is a leading cause of bile duct injury during cholecystectomy.

TMU Slide 6 (Gall-bladder Triangle section) · Gray’s Anatomy for Students 4e p.284

D2 Hepatopancreatic Ampulla (Ampulla of Vater) +

A short dilatation formed by the union of the common bile duct and the main pancreatic duct (duct of Wirsung) just before they open together into the duodenum. It opens on the summit of the major duodenal papilla on the posteromedial wall of the descending (2nd) part of the duodenum (D2), at approximately the level of L2. The circular smooth muscle surrounding the ampulla is thickened to form the sphincter of Oddi (sphincter of the hepatopancreatic ampulla), which controls the release of bile and pancreatic juice into the duodenum. Clinical significance: An impacted gallstone at the ampulla blocks both bile and pancreatic duct outflow simultaneously → obstructive jaundice + biliary pancreatitis. The minor duodenal papilla (~2 cm above) carries only the accessory pancreatic duct (of Santorini). ERCP (endoscopic retrograde cholangiopancreatography) cannulates the ampulla via the major papilla.

TMU Slide 6 (Common Bile Duct section) · 2020 Past Paper Definition Q2 · Gray’s Anatomy 4e p.293

D3 Bronchopulmonary Segment +

The smallest independent unit of lung tissue that can be surgically resected without devascularising adjacent lung tissue. Each segment is supplied by its own segmental bronchus, its own segmental artery (branch of pulmonary artery), and its own segmental vein (intersegmental, running in the connective tissue septa between adjacent segments). The TMU slide states: “The lobes of lung are subdivided into smaller units having independence structure and function and are called the bronchopulmonary segments. Each lung has ten segments.” There are 10 segments per lung (right lung: 3 lobes with 10; left lung: 2 lobes with 8–10). Clinical significance: Segmental resection (segmentectomy) allows removal of tumour or bronchiectasis while preserving maximum lung function. Radiological consolidation or collapse in a bronchopulmonary segment corresponds to obstruction of its feeding bronchus.

TMU Slide 6 (Section 6 Lungs) · 2022 Review Slide 9 (Concept: bronchial tree) · Gray’s Anatomy 4e p.172

D4 Costodiaphragmatic Recess (Costophrenic Recess) +

The lowest portion of the pleural cavity, formed where the costal pleura reflects onto the diaphragmatic pleura. The TMU slide states verbatim: “The costal and diaphragmatic pleurae are in contact with each other to form the costodiaphragmatic recess. It is the lowest portion of the pleural cavity.” It extends approximately 2 rib spaces below the inferior lung margin — i.e. the inferior pleural reflection is at the 8th rib (MCL), 10th rib (midaxillary line), and T12 spine (posterior). The lung does not enter this recess during quiet breathing, only during deep inspiration. Clinical significance: Free pleural fluid (effusion, blood, exudate, transudate) pools here by gravity. Blunting of the costophrenic angle on chest X-ray is the earliest radiological sign of a pleural effusion (~200 mL required on PA CXR). Therapeutic thoracocentesis is inserted into this recess (8th–9th ICS, posterior axillary line, upper border of rib to avoid neurovascular bundle).

TMU Slide 6 (Section 7 Pleura) · 2022 Review Slide 9 (Concept) · Gray’s Anatomy 4e p.176

D5 Porta Hepatis +

The transverse fissure on the inferior (visceral) surface of the liver, forming the horizontal crossbar of the H-shaped fissure. The TMU slide states: “The porta hepatis… may be regarded as the hilum of the liver.” Structures passing through the porta hepatis (the hepatic pedicle): entering — hepatic portal vein (posterior), proper hepatic artery (left), hepatic nerve plexus; emerging — right and left hepatic ducts, lymph vessels. The structures NOT transmitted include: hepatic veins (which exit posteriorly, directly into the IVC). Clinical significance: Pringle’s manoeuvre compresses the hepatoduodenal ligament (free right edge of lesser omentum) — which carries the porta hepatis structures between liver and duodenum — to temporarily stop hepatic inflow bleeding during liver surgery. A classic past paper MCQ trap asks which structure is NOT transmitted through the porta hepatis: answer = hepatic veins.

TMU Slide 6 (Porta Hepatis section); 2022 Review Slide 6 (Concept) · Gray’s Anatomy 4e p.278

D6 Cricothyroid Membrane (Cricothyroid Ligament) +

A fibrous membrane (part of the conus elasticus) connecting the inferior border of the thyroid cartilage to the superior border of the cricoid cartilage anteriorly. The TMU slide describes it as: “The part between the inferior border of the thyroid cartilage and the superior border of the cricoid cartilage is called the median cricothyroid ligament.” It is approximately 9 mm high and 30 mm wide. The superior free border of the conus elasticus forms the vocal ligament. Clinical significance: The cricothyroid membrane is the site of emergency cricothyrotomy — the fastest surgical airway when intubation fails (“can’t intubate, can’t oxygenate” scenario). Landmarks: palpate the thyroid notch → step down to the soft midline space between thyroid and cricoid cartilages → incise horizontally (or insert large-bore needle for needle cricothyrotomy). It is avascular (no major vessels) in the midline, making it safe for emergency access. The cricoid ring below is the only complete tracheal ring — preventing complete collapse.

TMU Slide 6 (Conus Elasticus / Laryngeal Ligaments) · ANATOMY_MASTER 6.5.2 · Gray’s Anatomy 4e p.149

Essay 1

Describe the liver: its lobes, diaphragmatic and visceral surfaces, peritoneal ligaments, dual blood supply, and the porta hepatis. Include the clinical importance of the bare area.

10 marks

General Description

The liver is the largest gland in the body (1.2–1.5 kg in males). It is wedge-shaped, reddish-brown, and lies mainly in the right hypochondriac and epigastric regions, with a small portion extending into the left hypochondriac region. It has two surfaces: diaphragmatic and visceral.

Diaphragmatic Surface (Superior/Anterior)

Smooth and domed, related to the diaphragm
Falciform ligament: a double peritoneal fold connecting the liver to the anterior abdominal wall and diaphragm; it divides the liver into the superficial right (large) and left (small) lobes; its free lower border contains the ligamentum teres hepatis (obliterated umbilical vein)
Coronary ligament (anterior + posterior layers): peritoneal reflections from the diaphragm onto the liver; the space between the two layers = the bare area
Triangular ligaments (right + left): formed at the lateral extremities where the coronary layers meet
Bare area: the posterior part of the diaphragmatic surface devoid of peritoneum, lying directly on the diaphragm. Clinically significant: extraperitoneal route for infection spread; portosystemic anastomosis (portal ↔ phrenic veins)

Visceral (Inferior) Surface

Slightly concave; shows the H-shaped fissure
Left vertical line: anterior = fissure for ligamentum teres (round ligament); posterior = fissure for ligamentum venosum (obliterated ductus venosus)
Right vertical line: anterior = fossa for gallbladder; posterior = groove for IVC
Horizontal bar (crossbar) of H = porta hepatis
Four lobes visible from below: right, left, quadrate (between ligamentum teres and gallbladder), caudate (between ligamentum venosum and IVC)
Impressions: gastric, oesophageal, right renal, duodenal, colic

Porta Hepatis

The hilum of the liver, transmitting (entering): portal vein (posterior), proper hepatic artery (left); (exiting): right and left hepatic ducts, lymph vessels. The hepatic veins are NOT transmitted here — they exit posteriorly directly into the IVC. These structures together form the hepatic pedicle.

Dual Blood Supply

Portal vein: ~75% of blood volume; nutrient-rich, relatively deoxygenated; drains GI tract + spleen
Hepatic artery proper (from common hepatic → coeliac trunk): ~25% of volume but ~50% of oxygen; fully oxygenated; essential for bile duct epithelium
Both vessels enter at the porta hepatis; blood mingles in hepatic sinusoids; exits via hepatic veins (right/middle/left) → IVC at T8

Ligamentum Teres and Ligamentum Venosum

Both are embryological remnants. Ligamentum teres = obliterated umbilical vein (foetal: carries oxygenated blood from placenta); useful as a guide to the left portal vein in surgery. Ligamentum venosum = obliterated ductus venosus (foetal bypass from portal to IVC).

Marking (10 marks): Diaphragmatic surface + ligaments (2) · Visceral surface + H-shaped fissure + four lobes (2) · Porta hepatis — correct structures in/out (2) · Dual blood supply with correct proportions (2) · Bare area significance (1) · Ligamentum teres/venosum embryological origin (1)

Essay 2

Describe the extrahepatic biliary apparatus: the gallbladder (parts, surface marking), bile ducts, Calot’s triangle, the hepatopancreatic ampulla, and the clinical significance of each.

8 marks

The Gallbladder

Pear-shaped; 7–10 cm long, 3–5 cm wide, 40–60 mL capacity. Stores and concentrates bile. Parts: Fundus (rounded tip) + Body (main part, related to visceral liver surface) + Neck (tapers, continues as cystic duct; the mucosa here forms the spiral valve of Heister) + Cystic duct (~3–4 cm; joins common hepatic duct to form common bile duct).

Surface marking of the fundus: where the lateral border of the right rectus abdominis crosses the costal arch (tip of 9th costal cartilage). This is the site of Murphy’s sign in acute cholecystitis.

Bile Ducts

Right and left hepatic ducts: emerge from porta hepatis → unite as common hepatic duct
Common hepatic duct + cystic duct → common bile duct (CBD) (~4–8 cm, 6–8 mm diameter)
CBD descends in the right border of the lesser omentum, behind D1 duodenum, then behind the head of the pancreas, uniting with the main pancreatic duct → hepatopancreatic ampulla (of Vater)
Ampulla opens at the major duodenal papilla on the posteromedial wall of D2; guarded by the sphincter of Oddi

Calot’s Triangle

Bounded by: cystic duct (inferior), common hepatic duct (medial), inferior surface of liver (superior). Contents: cystic artery (from right hepatic artery in ~62%). Essential to identify in cholecystectomy to avoid bile duct injury.

Bile Flow

Fasting: bile produced by hepatocytes → hepatic ducts → common hepatic duct → CBD → cystic duct (reflux) → gallbladder (store + concentrate)
Eating (CCK released): gallbladder contracts → cystic duct → CBD → ampulla → major papilla → duodenum (digest fat)

Clinical Correlations

Gallstone in CBD → obstructive jaundice (pale stools, dark urine, pruritus)
Stone at ampulla blocks both CBD and pancreatic duct → biliary pancreatitis
Carcinoma of pancreatic head compresses CBD → painless jaundice + Courvoisier’s sign (palpable gallbladder)
ERCP cannulates the major papilla to remove CBD stones or place stents

Marking (8 marks): Gallbladder parts + surface marking (1.5) · Bile ducts in correct sequence (1.5) · Common bile duct relations + sphincter of Oddi (1) · Calot’s triangle boundaries + cystic artery (1.5) · Bile flow fasting vs eating (1) · Two or more clinical correlations (1.5)

Essay 3

Describe the root of the lung (VABNS mnemonic), the fissures and lobes of each lung, and the bronchopulmonary segments. What makes the right main bronchus clinically dangerous for foreign body aspiration?

8 marks

Root of the Lung

The root of the lung is a short, broad pedicle connecting the lung to the mediastinum at the hilum (a depression on the mediastinal surface). The TMU slide states it consists of: bronchi, pulmonary artery and veins, nerves, bronchial vessels, lymphatics and lymph nodes.

Arrangement at the hilum (using VABNS mnemonic — from above downward, right side): Vein (pulmonary veins — anterior and below), Artery (pulmonary artery — superior), Bronchus (posterior and below on right; superior on left), Nerves, Sympathetic/bronchial vessels. Classically: on both sides, the bronchus is posterior and the pulmonary artery is anterior and superior. Two pulmonary veins exit anteroinferiorly.

Fissures and Lobes

Right lung: divided by two fissures — oblique fissure (separates upper+middle from lower) + horizontal fissure (separates upper from middle) → 3 lobes (upper, middle, lower)
Left lung: divided by one fissure — oblique fissure only → 2 lobes (upper, lower). The left upper lobe has a lingula (cardiac notch creates this tongue-shaped projection) = functional homologue of the right middle lobe
Right lung: shorter + wider; left lung: longer + narrower (accommodates heart on left)

Bronchopulmonary Segments

Each lung has 10 bronchopulmonary segments (right: 3+2+5 per lobe; left: 5+5 per lobe approximately). Each segment has its own segmental bronchus, artery, and intersegmental vein. They are the smallest independently resectable lung units. Radiologically, a consolidation or collapse within one segment = obstruction of its feeding bronchus.

Foreign Body Aspiration — Why the Right?

Right bronchus is shorter (2–3 cm vs left 4–5 cm)
Right bronchus is wider in diameter
Right bronchus is more vertical — takes a more direct downward course from the trachea
Carina deviates to the left — meaning the right bronchus continues more in line with the tracheal axis
Result: aspirated material preferentially enters the right, typically lodging in the right lower lobe bronchus (most vertical segment of the right bronchial tree)

Marking (8 marks): Root of lung — correct structures named (1.5) · Fissures and lobes right lung (1.5) · Fissures and lobes left lung + lingula (1) · Bronchopulmonary segments defined + correct number (1.5) · Four anatomical reasons for right-sided foreign body aspiration (2) · Lingula as homologue of right middle lobe (0.5)

Essay 4

Describe the trachea and principal bronchi: structure, relations, vertebral levels, and differences between left and right bronchus. Why are foreign bodies dangerous in the right bronchus in particular?

8 marks

The Trachea

Extent: from lower border of cricoid cartilage (C6) to bifurcation at T4/T5 (level of sternal angle)
Length: ~10 cm; diameter: 1.5–2 cm
Position: midline of neck + upper thorax; lies in front of the oesophagus
Structure: wall composed of 14–17 C-shaped hyaline cartilage rings (open posteriorly), smooth muscle (trachealis) + connective tissue at the posterior wall — the pars membranacea (allows oesophageal expansion during swallowing)
Carina: internal sagittal semilunar ridge at the bifurcation, visible on bronchoscopy; normally positioned left of midline (a widened, fixed carina suggests carinal node invasion by tumour)

Relations of the Trachea

In the neck: thyroid gland (lobes anterolateral, isthmus crosses rings 2–4), thyroid arteries, carotid sheath laterally
In the thorax: aortic arch crosses left side at T4, left recurrent laryngeal nerve (hooks under aortic arch), SVC and brachiocephalic veins anteriorly

The Principal (Main) Bronchi

Feature	Right Bronchus	Left Bronchus
Length	Shorter (2–3 cm)	Longer (4–5 cm)
Diameter	Wider	Narrower
Orientation	More vertical	More oblique (horizontal)
Structures crossing	Azygos vein arches over it	Aortic arch above; descending aorta and oesophagus posteriorly
Foreign body	More common (preferential)	Less common

Foreign Body Aspiration — Danger in the Right

Because the right bronchus is shorter, wider, and more vertical, and the carina sits left of midline, aspirated material travels preferentially into the right main bronchus and most commonly lodges in the right lower lobe bronchus. Consequences: distal atelectasis (collapse), post-obstructive pneumonia, abscess, or ball-valve air trapping (obstructive emphysema). Heimlich manoeuvre (fist between umbilicus and costal arch, inward-upward thrust) uses sudden subdiaphragmatic pressure to expel foreign bodies from the larynx/trachea.

Marking (8 marks): Tracheal extent C6–T4/5 (1) · Structure: C-shaped rings + pars membranacea (1) · Carina described (0.5) · Relations (1) · Right vs left bronchus table — 4 features (2) · Three reasons for right-sided aspiration (1.5) · Consequences of foreign body lodgement (1)

Essay 5

Describe the mediastinum: its boundaries, divisions, and the main contents of each division. What are the “4 T’s” of the anterior mediastinum?

8 marks

Definition and Boundaries

The TMU slide defines the mediastinum as: “the interval between the right and left pleural sacs” — the bulky septum between the mediastinal pleurae. Overall boundaries: Anteriorly = sternum and costal cartilages; Posteriorly = thoracic vertebrae; Laterally = mediastinal pleura (right and left); Superiorly = thoracic inlet (superior aperture); Inferiorly = diaphragm.

Divisions

Divided into superior and inferior by a transverse plane through the sternal angle (angle of Louis) at T4/T5. The inferior mediastinum is further subdivided by the pericardium:

Anterior = in front of the pericardium
Middle = within the pericardium (pericardial sac)
Posterior = behind the pericardium

Contents of Each Division

Superior mediastinum (above sternal angle): aortic arch and its three branches (brachiocephalic trunk, left common carotid, left subclavian), SVC (formation), brachiocephalic veins, trachea, oesophagus, thoracic duct (upper part), thymus (involuted), phrenic nerves, vagus nerves, left recurrent laryngeal nerve (hooks under aortic arch), cardiac nerves.

Anterior mediastinum (inferior, in front of pericardium): thymus (lower part in children), internal thoracic vessels (lower part), lymph nodes, connective tissue + fat. Site of the 4 T’s (see below).

Middle mediastinum (within pericardium): heart + pericardium, ascending aorta, pulmonary trunk (and proximal arteries), SVC (lower end), pulmonary veins (entering LA), phrenic nerves (with pericardiacophrenic vessels) on each side.

Posterior mediastinum (behind pericardium): oesophagus, descending thoracic aorta, thoracic duct (main portion), azygos and hemi-azygos veins, sympathetic trunks, greater/lesser splanchnic nerves, posterior intercostal vessels, vagus nerves (oesophageal plexus).

The 4 T’s of the Anterior Mediastinum

Thymoma: most common anterior mediastinal mass in adults over 40; strongly associated with myasthenia gravis (50% of thymoma patients have MG; 15% of MG patients have thymoma). Can be malignant.
Teratoma (germ cell tumour): most common anterior mediastinal mass in young adults; may contain hair, teeth, sebaceous material (mature teratoma); can be malignant (non-seminomatous GCT). AFP/β-HCG elevated in malignant types.
Thyroid (retrosternal goitre): enlarged thyroid descends through thoracic inlet into the anterior mediastinum; presents with stridor, dysphagia, SVC syndrome. Moves on swallowing.
Terrible lymphoma: both Hodgkin’s (nodular sclerosis type most common in anterior mediastinum — “young woman with bulky anterior mediastinal mass”) and non-Hodgkin’s (mediastinal large B-cell lymphoma). Most common overall anterior mediastinal mass in young adults.

Marking (8 marks): Definition and overall boundaries (1) · Division by sternal angle into superior/inferior (0.5) · Sub-division of inferior into anterior/middle/posterior (0.5) · Superior mediastinum contents — key structures (1.5) · Middle mediastinum = heart + phrenic nerves (1) · Posterior mediastinum — 4 main structures (1) · 4 T’s of anterior mediastinum with one clinical note each (2.5)

Unit 06 — Alimentary Glands & Respiratory System · Question Bank

General Description

Diaphragmatic Surface (Superior/Anterior)

Visceral (Inferior) Surface

Porta Hepatis

Dual Blood Supply

Ligamentum Teres and Ligamentum Venosum

The Gallbladder

Bile Ducts

Calot’s Triangle

Bile Flow

Clinical Correlations

Root of the Lung

Fissures and Lobes

Bronchopulmonary Segments

Foreign Body Aspiration — Why the Right?

The Trachea

Relations of the Trachea

The Principal (Main) Bronchi

Foreign Body Aspiration — Danger in the Right

Definition and Boundaries

Divisions

Contents of Each Division

The 4 T’s of the Anterior Mediastinum