Abdominal Anatomy

1. Quick Answer

Abdominal anatomy encompasses the structures from the diaphragm superiorly to the pelvic inlet inferiorly, including the abdominal wall (muscles and fascial layers), peritoneum (parietal and visceral), solid organs (liver, spleen, kidneys, pancreas), hollow viscera (stomach, small intestine, large intestine, gallbladder), and major vessels (aorta, IVC, portal system).

Key Concepts:

• The abdominal wall has three muscular layers: external oblique, internal oblique, and transversus abdominis
• The peritoneum creates intraperitoneal and retroperitoneal compartments with clinical significance for infection spread
• The liver has eight functionally independent segments (Couinaud classification) based on portal vein branches
• The portal venous system drains all abdominal GI tract blood to the liver for first-pass metabolism

ICU Relevance:

• Critical for central venous access (femoral vein), paracentesis, feeding tube placement, and laparoscopic surgery
• Understanding of abdominal compartment syndrome and intra-abdominal hypertension
• Knowledge of portal hypertension anatomy guides variceal bleeding management
• Applied anatomy for percutaneous procedures (PEG, cholecystostomy, nephrostomy)

Exam Focus:

• CICM First Part examiners commonly ask about Couinaud liver segments, portal venous anatomy, and applied anatomy for ICU procedures

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2. CICM First Part Exam Focus

What Examiners Expect

Written SAQ:

Common question stems:

• "Describe the anatomy of the anterior abdominal wall with particular reference to the layers encountered during laparoscopy port insertion"
• "Draw and label the Couinaud classification of liver segments and explain its clinical significance"
• "Outline the anatomy of the portal venous system and describe the sites of portosystemic anastomoses"
• "Describe the anatomy relevant to paracentesis in the left iliac fossa"
• "Describe the blood supply to the stomach and its relevance to gastric surgery"

Expected depth:

• Detailed anatomical knowledge with named structures and relationships
• Clear understanding of fascial layers and their continuity
• Blood supply (arterial and venous) with collateral pathways
• Clear diagrams with accurate labeling
• Explicit ICU application (procedures, pathophysiology of critical illness)

Written MCQ:

Common topics tested:

• Abdominal wall layers and their nerve supply
• Peritoneal attachments (mesenteries, ligaments, omenta)
• Liver segmental anatomy and blood supply
• Portal vein tributaries and portosystemic anastomoses
• Arterial supply to the GI tract (coeliac, SMA, IMA territories)
• Anatomical relationships of retroperitoneal structures

Difficulty level:

• Applied anatomical scenarios (e.g., "During laparoscopic cholecystectomy, what structure lies immediately posterior to the gallbladder neck?")
• Identification of structures from cross-sectional descriptions
• Clinical consequences of vascular injury or obstruction

Oral Viva:

Expected discussion flow:

1. Define/Describe - Overview of abdominal regions and divisions
2. Detail Structure - Layers, muscles, fasciae, peritoneal folds
3. Organ Systems - Solid organs, hollow viscera, relationships
4. Blood Supply - Arterial supply (coeliac, SMA, IMA), venous drainage (portal, systemic)
5. Apply to ICU - Paracentesis, laparoscopy, feeding tubes, abdominal compartment syndrome
6. Clinical Correlation - Portal hypertension, bowel ischemia, abdominal trauma

Common viva scenarios:

• "Walk me through the anatomy encountered when inserting a peritoneal dialysis catheter"
• "A patient develops portal hypertension. Explain the anatomical basis of the clinical manifestations"
• "Describe the blood supply to the colon and implications for bowel ischemia"

Pass vs Fail Performance

Pass Standard:

• Accurate description of abdominal wall layers and their relationships
• Clear understanding of Couinaud liver segments and portal triad
• Correct description of portal venous system and portosystemic anastomoses
• Ability to describe surface landmarks for procedures
• Draws clear diagrams of abdominal regions and organ relationships

Common Reasons for Failure:

• Confusing intraperitoneal and retroperitoneal structures
• Inability to describe the portal vein formation and tributaries
• Not knowing the arterial territories of the coeliac trunk, SMA, and IMA
• Cannot identify the layers encountered during laparoscopy
• Poor understanding of the watershed areas of colonic blood supply

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3. Key Points

Must-Know Facts

1. Abdominal Wall Muscles: Three flat muscles (external oblique, internal oblique, transversus abdominis) with fibres running in different directions. The rectus abdominis is enclosed in the rectus sheath; below the arcuate line, all aponeuroses pass anterior to the rectus (PMID: 30844173).

2. Rectus Sheath: Above the arcuate line: anterior wall = external oblique + anterior layer of internal oblique; posterior wall = posterior layer of internal oblique + transversus abdominis. Below arcuate line: ALL aponeuroses pass ANTERIOR to rectus; posterior wall = transversalis fascia only.

3. Inguinal Canal: 4cm oblique passage through abdominal wall. Contents: spermatic cord (males) or round ligament (females). Deep ring at transversalis fascia; superficial ring at external oblique aponeurosis. Floor = inguinal ligament (PMID: 29630219).

4. Peritoneum: Largest serous membrane. Parietal peritoneum is pain-sensitive (somatic afferents T7-L1); visceral peritoneum is pain-insensitive (autonomic afferents). Peritoneal cavity contains only a thin film of serous fluid (~50-100mL) (PMID: 29261867).

5. Portal Vein: Formed behind neck of pancreas by union of superior mesenteric vein and splenic vein. NO VALVES. Carries 1500mL/min (75% of hepatic blood flow) but only 50% of hepatic oxygen. Enters liver at porta hepatis with hepatic artery and bile duct (portal triad) (PMID: 26740008).

6. Couinaud Liver Segments: Eight functionally independent segments based on portal vein branches. Divided by hepatic veins (right, middle, left). Segment I (caudate) is unique - receives blood from both portal branches and drains directly to IVC (PMID: 11054688).

7. Splenic Anatomy: Left upper quadrant, ribs 9-11 posterolaterally. Suspended by lienorenal and gastrosplenic ligaments. Blood supply from splenic artery (largest coeliac branch). Most commonly injured organ in blunt abdominal trauma (PMID: 29083568).

8. SMA Territory: Supplies all small intestine (jejunum, ileum), cecum, ascending colon, and proximal 2/3 of transverse colon (to splenic flexure). SMA occlusion causes massive intestinal infarction. Watershed at splenic flexure with IMA (PMID: 28698207).

9. Portal-Systemic Anastomoses: Five sites - (1) Lower esophagus (left gastric → esophageal → azygos), (2) Umbilicus (paraumbilical → superficial epigastric), (3) Rectum (superior rectal → middle/inferior rectal), (4) Retroperitoneum (colic → lumbar), (5) Liver (portal → phrenic) (PMID: 26740008).

10. Abdominal Compartment Syndrome: Sustained IAP >20 mmHg with new organ dysfunction. Normal IAP 5-7 mmHg. Diagnosed by intravesical pressure measurement. Understanding of abdominal compliance and organ blood flow relationships essential (PMID: 26720449).

Essential Anatomical Relationships

Portal Triad (Hepatoduodenal Ligament):

• Anterior: Common bile duct (right)
• Posterior: Portal vein
• Left: Hepatic artery proper
• Clinical significance: Pringle manoeuvre (clamping to control hepatic hemorrhage)

Transpyloric Plane (L1 level):

• Pylorus of stomach
• Fundus of gallbladder
• Neck of pancreas
• Hilum of kidneys
• Origin of SMA
• Termination of spinal cord

Normal Values Table

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4. Abdominal Wall

4.1 Surface Anatomy

Abdominal Regions

Nine-Region System: The abdomen is divided by two vertical (mid-clavicular) and two horizontal (subcostal at L3, transtubercular at L5) planes:

Four-Quadrant System: Divided by median plane and transumbilical plane (L3-L4):

• Right upper quadrant (RUQ): Liver, gallbladder, right kidney, hepatic flexure
• Left upper quadrant (LUQ): Stomach, spleen, left kidney, splenic flexure
• Right lower quadrant (RLQ): Appendix, cecum, right ovary/spermatic cord
• Left lower quadrant (LLQ): Sigmoid colon, left ovary/spermatic cord

Key Surface Landmarks:

McBurney's Point: Junction of lateral 1/3 and medial 2/3 of line from umbilicus to ASIS. Corresponds to base of appendix (PMID: 30252265).

4.2 Abdominal Wall Muscles

Flat Muscles (Anterolateral Wall)

External Oblique:

• Origin: Lower 8 ribs (interdigitating with serratus anterior and latissimus dorsi)
• Insertion: Anterior half of iliac crest, pubic tubercle, linea alba
• Fibre direction: "Hands in pockets"
• superomedial to inferolateral
• Aponeurosis: Forms anterior rectus sheath above arcuate line, inguinal ligament, superficial inguinal ring
• Innervation: T7-T12 intercostal nerves, iliohypogastric (L1)
• Function: Trunk rotation (contralateral), lateral flexion (ipsilateral), abdominal compression

PMID: 30844173

Internal Oblique:

• Origin: Thoracolumbar fascia, anterior 2/3 of iliac crest, lateral 2/3 of inguinal ligament
• Insertion: Lower 3-4 ribs, linea alba, pubic crest (via conjoint tendon)
• Fibre direction: Perpendicular to external oblique - inferolateral to superomedial
• Aponeurosis: Splits above arcuate line - anterior layer joins external oblique, posterior layer joins transversus
• Innervation: T7-L1 intercostal and subcostal nerves, iliohypogastric, ilioinguinal
• Function: Trunk rotation (ipsilateral), lateral flexion, abdominal compression

Transversus Abdominis:

• Origin: Lower 6 costal cartilages (interdigitating with diaphragm), thoracolumbar fascia, anterior 2/3 of iliac crest, lateral 1/3 of inguinal ligament
• Insertion: Linea alba, pubic crest (via conjoint tendon)
• Fibre direction: Horizontal (transverse)
• Aponeurosis: Forms posterior rectus sheath above arcuate line; all passes anterior below arcuate line
• Innervation: T7-L1 intercostal and subcostal nerves, iliohypogastric, ilioinguinal
• Function: Abdominal compression, expiration

Clinical Application - Transversus Abdominis Plane (TAP) Block: The TAP block provides analgesia for abdominal wall incisions. Local anaesthetic is deposited between internal oblique and transversus abdominis, blocking T7-L1 nerves. Ultrasound-guided technique is standard (PMID: 25919621).

Rectus Abdominis

• Origin: Pubic crest, pubic symphysis
• Insertion: Xiphoid process, 5th-7th costal cartilages
• Structure: Strap muscle with 3-4 tendinous intersections (adherent to anterior sheath)
• Innervation: T7-T12 intercostal nerves (segmental)
• Function: Trunk flexion, increases intra-abdominal pressure
• Blood supply: Superior epigastric artery (from internal thoracic), inferior epigastric artery (from external iliac)

Clinical Application: The rectus abdominis is split longitudinally in a midline laparotomy; the linea alba is an avascular plane. Paramedian incisions divide the anterior rectus sheath and retract the muscle laterally.

Pyramidalis

• Small triangular muscle anterior to rectus (absent in 20%)
• Origin: Pubic crest
• Insertion: Linea alba
• Function: Tenses linea alba

4.3 Fascial Layers

Superficial Fascia

Camper's Fascia (Fatty Layer):

• Superficial layer of superficial fascia
• Contains subcutaneous fat
• Continues inferiorly as superficial fascia of thigh

Scarpa's Fascia (Membranous Layer):

• Deep layer of superficial fascia
• Attached firmly to inguinal ligament and fascia lata below
• Continues into perineum as Colles' fascia
• Important for spread of urinary extravasation

Deep Fascia

Transversalis Fascia:

• Lines the entire abdominal cavity deep to transversus abdominis
• Forms deep inguinal ring
• Continuous with iliac fascia, pelvic fascia, and posterior rectus sheath (above arcuate line)
• Extraperitoneal fat lies between transversalis fascia and parietal peritoneum

Fascia Transversalis:

• The internal spermatic fascia is derived from transversalis fascia at the deep ring
• Important in hernia anatomy

4.4 Rectus Sheath

The rectus sheath is formed by the aponeuroses of the three flat muscles:

Above the Arcuate Line (Approximately Midway Between Umbilicus and Pubis):

Below the Arcuate Line:

Arcuate Line (of Douglas):

• Level: Approximately 1/3 of distance from umbilicus to pubis
• Represents the point where all aponeuroses pass anterior to rectus
• Below this, posterior rectus sheath is absent - only transversalis fascia separates rectus from peritoneum
• Clinical significance: Reduced support for rectus, more prone to rectus sheath hematoma below this level

PMID: 30969621

Contents of Rectus Sheath:

• Rectus abdominis muscle
• Pyramidalis muscle (lower portion)
• Superior and inferior epigastric vessels
• T7-T12 intercostal nerves (enter laterally)
• Lymphatics

Linea Alba:

• Fibrous midline raphe from xiphoid to pubic symphysis
• Fusion of all three aponeuroses
• Relatively avascular - preferred site for midline laparotomy
• Width: 1-2cm (wider above umbilicus)
• Umbilicus is a defect in linea alba

Linea Semilunaris:

• Lateral border of rectus abdominis
• Represents transition from muscle to aponeurosis of flat muscles
• Spigelian hernia occurs at this site

4.5 Inguinal Canal

Definition: An oblique passage (4cm in adults) through the lower anterior abdominal wall, transmitting the spermatic cord (males) or round ligament (females).

Boundaries:

Inguinal Ligament (Poupart's Ligament):

• Formed by the infolded lower edge of external oblique aponeurosis
• Extends from ASIS to pubic tubercle
• Forms floor of inguinal canal
• Femoral vessels pass posterior to its medial portion

Deep (Internal) Inguinal Ring:

• An opening in transversalis fascia
• Location: 1.5cm above midpoint of inguinal ligament
• Relationship: Lateral to inferior epigastric vessels
• Transversalis fascia evaginates as internal spermatic fascia

Superficial (External) Inguinal Ring:

• A triangular opening in external oblique aponeurosis
• Location: Superior and lateral to pubic tubercle
• Boundaries: Superior crus, inferior crus, intercrural fibres
• External oblique aponeurosis evaginates as external spermatic fascia

Contents:

Three Coverings of Spermatic Cord:

1. External spermatic fascia (from external oblique)
2. Cremasteric fascia and muscle (from internal oblique)
3. Internal spermatic fascia (from transversalis fascia)

Hasselbach's Triangle (Inguinal Triangle):

• Site of direct inguinal hernia (medial to inferior epigastric vessels)
• Boundaries:
  • "Lateral: Inferior epigastric vessels"
  • "Medial: Lateral border of rectus abdominis"
  • "Inferior: Inguinal ligament"

PMID: 29630219

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5. Peritoneum

5.1 General Organization

Definition: The largest serous membrane of the body, consisting of a single layer of mesothelial cells supported by connective tissue. Total surface area approximately 1.7-2.0 m² (similar to skin surface area).

Parietal Peritoneum:

• Lines the inner surface of the abdominal wall
• Derived from somatic mesoderm
• Innervation: Somatic afferents (T7-L1 intercostal, subcostal, iliohypogastric, ilioinguinal nerves)
• Sensation: Sharp, well-localized pain (like skin)
• Blood supply: From abdominal wall vessels

Visceral Peritoneum:

• Covers abdominal viscera
• Derived from splanchnic mesoderm
• Innervation: Autonomic afferents (sympathetic via splanchnic nerves)
• Sensation: Dull, poorly localized pain (referred to dermatomes)
• Blood supply: From visceral vessels

Clinical Significance: Parietal peritoneal irritation (e.g., by appendicitis reaching the peritoneum) causes localized tenderness and guarding. Visceral pain (early appendicitis) is referred to the umbilical region (T10 dermatome).

PMID: 29261867

5.2 Peritoneal Cavity

Definition: A potential space between parietal and visceral peritoneum. Contains only a thin film of serous fluid (50-100mL) that lubricates movement.

Greater Sac: The main peritoneal cavity, subdivided by the transverse mesocolon into:

• Supracolic compartment: Above transverse mesocolon (stomach, liver, spleen)
• Infracolic compartment: Below transverse mesocolon (small intestine, ascending/descending colon)

Lesser Sac (Omental Bursa): A diverticulum of the greater sac posterior to the stomach and lesser omentum.

Epiploic (Omental) Foramen of Winslow:

• The only communication between greater and lesser sacs
• Location: Between hepatoduodenal ligament (anteriorly) and IVC (posteriorly)
• Boundaries:
  • "Anterior: Hepatoduodenal ligament (portal triad)"
  • "Posterior: IVC (covered by peritoneum)"
  • "Superior: Caudate lobe of liver"
  • "Inferior: First part of duodenum"
• Clinical significance: Site of Pringle manoeuvre access; can be occluded by inserting finger and compressing portal triad to control hepatic hemorrhage

5.3 Intraperitoneal vs Retroperitoneal Organs

Intraperitoneal (Completely Covered):

• Stomach
• Liver (except bare area)
• Spleen
• Jejunum and ileum
• Transverse colon
• Sigmoid colon
• First 2cm of duodenum
• Cecum (variable - may be retrocecal)
• Appendix

Secondarily Retroperitoneal (Originally Intraperitoneal):

• Duodenum (D2-D4)
• Ascending colon
• Descending colon
• Pancreas (except tail)
• Upper 2/3 of rectum

Primarily Retroperitoneal:

• Kidneys and ureters
• Adrenal glands
• Aorta and IVC
• Lymph nodes

Mnemonic for Retroperitoneal Structures: SAD PUCKER

• Suprarenal glands
• Aorta/IVC
• Duodenum (2nd-4th parts)
• Pancreas (head, neck, body)
• Ureters
• Colon (ascending, descending)
• Kidneys
• Esophagus (thoracic portion is posterior mediastinum)
• Rectum (lower 1/3)

5.4 Peritoneal Folds, Mesenteries, and Ligaments

Mesenteries (double layer of peritoneum attaching organs to posterior abdominal wall, containing vessels, nerves, lymphatics, fat):

Omenta:

Lesser Omentum:

• Extends from lesser curvature of stomach and first 2cm of duodenum to liver
• Two parts:
  • Hepatogastric ligament (stomach to liver - thin, can be divided)
  • Hepatoduodenal ligament (duodenum to liver - contains portal triad)
• Portal triad within hepatoduodenal ligament:
  • Common bile duct (right, anterior)
  • Hepatic artery proper (left, anterior)
  • Portal vein (posterior)

Greater Omentum:

• Four-layered apron hanging from greater curvature of stomach
• Attaches to transverse colon
• Contains variable amounts of fat
• "Policeman of the abdomen"
• migrates to sites of inflammation
• Blood supply: Right and left gastroepiploic arteries

Peritoneal Ligaments of Solid Organs:

5.5 Peritoneal Recesses and Pouches

Paracolic Gutters:

• Channels between ascending/descending colon and lateral abdominal wall
• Right paracolic gutter is continuous with hepatorenal recess (Morison's pouch)
• Left paracolic gutter is interrupted by phrenicocolic ligament
• Infected fluid preferentially flows right → right paracolic gutter → hepatorenal recess → right subphrenic space

Morison's Pouch (Hepatorenal Recess):

• Deepest part of peritoneal cavity in supine position
• Between right lobe of liver and right kidney
• First site where free fluid accumulates in supine trauma patient
• Detected on FAST ultrasound

Subphrenic Spaces:

• Right subphrenic (between right lobe of liver and diaphragm)
• Left subphrenic (between left lobe of liver/stomach and diaphragm)
• Divided by falciform ligament
• Common sites for abscess formation following abdominal surgery

Rectouterine Pouch (Pouch of Douglas) - Females:

• Between uterus and rectum
• Deepest part of female peritoneal cavity in upright position
• Accessed via posterior vaginal fornix (culdocentesis)

Rectovesical Pouch - Males:

• Between rectum and bladder
• Deepest part of male peritoneal cavity in upright position

PMID: 28698208

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6. Liver

6.1 External Anatomy

Location and Size:

• Occupies right hypochondrium, epigastrium, and extends into left hypochondrium
• Weight: 1.2-1.5 kg (2% of body weight)
• Superior surface in contact with diaphragm (domes to 5th intercostal space on right)
• Inferior surface in contact with stomach, duodenum, colon, right kidney, right adrenal

Lobes (Anatomical):

• Right lobe: Largest, separated from left by falciform ligament (anterior) and ligamentum venosum (posterior)
• Left lobe: Smaller, extends to left of midline
• Caudate lobe: Posterior, between IVC and ligamentum venosum
• Quadrate lobe: Inferior, between gallbladder fossa and ligamentum teres

Note: Anatomical lobes do NOT correspond to functional surgical segments.

6.2 Couinaud Classification (Functional Segments)

The Couinaud classification divides the liver into 8 functionally independent segments based on portal vein branches, hepatic artery branches, and bile duct tributaries. Each segment has its own pedicle and can be resected independently.

Segmental Division:

Hepatic Vein Boundaries:

• Right hepatic vein: Separates right anterior (V, VIII) from right posterior (VI, VII) sectors
• Middle hepatic vein: Separates right lobe (V-VIII) from left lobe (II-IV)
• Left hepatic vein: Separates segments II from III

Mnemonic for Segment Numbering: Segments numbered clockwise starting from caudate (I) when viewing the liver from below (visceral surface).

Clinical Application:

• Segment I (caudate) is unique: receives blood from BOTH left and right portal branches, drains directly to IVC via hepatic veins (not main hepatic veins)
• This explains caudate hypertrophy in Budd-Chiari syndrome (hepatic vein thrombosis)

PMID: 11054688

6.3 Porta Hepatis

Definition: The hilum of the liver on the visceral surface where structures enter and exit.

Contents (Portal Triad):

• Portal vein (posterior): Largest structure, formed by SMV + splenic vein
• Hepatic artery proper (anterior, left): Branch of common hepatic (from coeliac trunk)
• Common hepatic duct (anterior, right): Drains bile to common bile duct

Relationship: The hepatic artery proper divides into right and left hepatic arteries at the porta hepatis.

Glisson's Capsule: Connective tissue sheath that invests the portal triad at the porta hepatis and extends into the liver parenchyma, separating segments.

6.4 Blood Supply

Dual Blood Supply (unique among abdominal organs):

Portal Vein:

• Formed behind neck of pancreas by union of SMV and splenic vein
• Length: 6-8 cm
• No valves (allows bidirectional flow)
• Tributaries: Left gastric vein (directly), cystic veins (directly)
• Divides into left and right branches at porta hepatis

Hepatic Artery Anatomy:

1. Coeliac trunk (T12 level from aorta)
2. Common hepatic artery (branch of coeliac)
3. Proper hepatic artery (after gastroduodenal artery branches off)
4. Right and left hepatic arteries (at porta hepatis)

Anatomical Variants (very common):

• Replaced right hepatic artery from SMA (10-15%)
• Replaced left hepatic artery from left gastric (10%)
• Replaced common hepatic artery from SMA (2%)

Hepatic Venous Drainage:

• Three main hepatic veins (right, middle, left) drain directly into IVC
• Caudate lobe has separate small veins draining directly to IVC
• No valves in hepatic veins

PMID: 26740008

6.5 Ligaments of the Liver

Bare Area of Liver:

• Posterior surface of right lobe in direct contact with diaphragm
• No peritoneal covering
• Bounded by coronary ligament (anterior and posterior layers)
• Clinical significance: Amoebic abscess may rupture into pleural cavity

6.6 Applied Anatomy

Pringle Manoeuvre:

• Compression of hepatoduodenal ligament to control hepatic hemorrhage
• Occludes portal vein and hepatic artery
• Reduces hepatic blood flow by 80%
• Tolerance: Intermittent occlusion for 15-20 minutes (ischemia preconditioning improves tolerance)
• PMID: 22542078

Liver Biopsy:

• Site: Right 9th-11th intercostal space, mid-axillary line
• Performed in expiration (liver descends)
• Risk: Hemorrhage, bile leak, pneumothorax

Hepatic Resection:

• Couinaud segments allow anatomical resections
• Right hepatectomy: Segments V-VIII
• Left hepatectomy: Segments II-IV
• Extended right hepatectomy: Segments IV-VIII

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7. Biliary System

7.1 Gallbladder

Anatomy:

• Pear-shaped organ on visceral surface of liver, in gallbladder fossa (between segments IV and V)
• Parts: Fundus (projects beyond liver edge), body, infundibulum (Hartmann's pouch), neck
• Capacity: 30-50 mL (can distend to 200 mL)
• Wall has no submucosa; mucosa directly on muscle layer

Relations:

• Superior: Liver (gallbladder fossa)
• Inferior: Transverse colon, duodenum
• Posterior: First part of duodenum

Surface Marking: Junction of right costal margin and lateral border of rectus abdominis (at transpyloric plane - L1)

Blood Supply:

• Cystic artery: Usually from right hepatic artery, passes posterior to common hepatic duct
• Drains via cystic veins to liver directly (portal branches)

Calot's Triangle (Cystohepatic Triangle):

• Boundaries:
  • "Superior: Inferior surface of liver (segment V)"
  • "Medial: Common hepatic duct"
  • "Inferior: Cystic duct"
• Contents: Cystic artery, cystic lymph node (of Lund)
• Critical view of safety: Must be achieved before clipping cystic artery/duct during laparoscopic cholecystectomy

PMID: 29939721

7.2 Bile Ducts

Intrahepatic Bile Ducts:

• Follow portal triad branches within liver parenchyma
• Right and left hepatic ducts emerge at porta hepatis

Common Hepatic Duct:

• Formed by union of right and left hepatic ducts at porta hepatis
• Length: 3-4 cm
• Lies anterior to portal vein, to the right of hepatic artery

Cystic Duct:

• Connects gallbladder neck to common hepatic duct
• Length: 2-4 cm (variable)
• Contains spiral valve of Heister (maintains patency)
• Variable insertion (may be low, joining at pancreatic head level)

Common Bile Duct (CBD):

• Formed by union of common hepatic duct and cystic duct
• Length: 7-8 cm
• Diameter: Normal <6 mm (increases with age, post-cholecystectomy up to 10 mm)
• Parts:
  1. Supraduodenal (in hepatoduodenal ligament)
  2. Retroduodenal (behind first part of duodenum)
  3. Pancreatic (within or behind head of pancreas)
  4. Intramural (passes through duodenal wall)

Ampulla of Vater (Hepatopancreatic Ampulla):

• Union of CBD and main pancreatic duct
• Opens into second part of duodenum at major duodenal papilla
• Surrounded by sphincter of Oddi

Sphincter of Oddi:

• Muscular sphincter surrounding ampulla of Vater
• Three components: Sphincter choledochus, sphincter pancreaticus, sphincter ampullae
• Controls flow of bile and pancreatic juice into duodenum
• Relaxed by CCK, contracted by sympathetic stimulation

Bile Duct Variations:

• Accessory hepatic duct draining directly to gallbladder or cystic duct (15%)
• Aberrant right hepatic duct crossing Calot's triangle (20%)
• Low insertion of cystic duct (common, increases CBD injury risk)

PMID: 29630220

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8. Spleen

8.1 Anatomy

Location:

• Left hypochondrium, posterior to stomach
• Ribs 9-11, posterolateral (long axis along 10th rib)
• Vertebral level: T10-L1

Size (normal):

• Length: 8-13 cm (rule of 1-3-5-7-9-11: 1 inch thick, 3 inches wide, 5 inches long, 7 ounces, 9th-11th ribs)
• Weight: 150-200 g

Surfaces:

• Diaphragmatic (lateral): Convex, in contact with diaphragm
• Visceral (medial): Concave, with impressions:
  • Gastric impression (anterior)
  • Renal impression (posterior)
  • Colic impression (inferior)

Hilum: On visceral surface, transmits splenic vessels and nerves.

PMID: 29083568

8.2 Peritoneal Attachments

Gastrosplenic Ligament:

• From greater curvature of stomach to splenic hilum
• Contains short gastric vessels, left gastroepiploic artery

Lienorenal (Splenorenal) Ligament:

• From left kidney to splenic hilum
• Contains splenic artery and vein, tail of pancreas

Phrenicocolic Ligament:

• From splenic flexure of colon to diaphragm
• Supports spleen, limits spread of infected fluid in left paracolic gutter

8.3 Blood Supply

Splenic Artery:

• Largest branch of coeliac trunk
• Tortuous course along superior border of pancreas
• Branches:
  • Pancreatic branches
  • Short gastric arteries (5-7, to fundus of stomach)
  • Left gastroepiploic artery (in gastrosplenic ligament)
• Terminates as superior and inferior terminal branches at hilum

Splenic Vein:

• Formed at hilum by union of terminal veins
• Lies posterior to pancreas
• Receives inferior mesenteric vein (usually)
• Joins SMV to form portal vein behind neck of pancreas

Clinical Significance:

• Splenic artery aneurysm (3rd most common intra-abdominal aneurysm)
• Splenic vein thrombosis causes isolated gastric varices (left-sided/sinistral portal hypertension)

8.4 Functions

1. Immunological: Largest lymphoid organ; B and T lymphocytes, macrophages, opsonization (especially for encapsulated organisms)
2. Filtration: Removal of old/damaged RBCs (culling), extraction of inclusions (pitting)
3. Reservoir: Up to 300 mL blood, 1/3 of platelets
4. Haematopoiesis: In fetal life (extramedullary haematopoiesis in pathological states)

Post-Splenectomy:

• Overwhelming post-splenectomy infection (OPSI) - risk of encapsulated organisms (Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis)
• Howell-Jolly bodies (nuclear remnants), target cells, thrombocytosis
• Requires vaccination and antibiotic prophylaxis

PMID: 26989196

8.5 Applied Anatomy

Splenomegaly:

• Enlarges towards umbilicus (along axis of 10th rib)
• Differentiated from left kidney by:
  • Notched anterior border
  • Cannot get above it
  • Moves with respiration
  • Dull to percussion

Splenic Trauma:

• Most commonly injured organ in blunt abdominal trauma
• Subcapsular hematoma may result in delayed rupture (2-10 days)
• Management: Observation (hemodynamically stable) vs angioembolization vs splenectomy

---

9. Stomach

9.1 Anatomy

Location: Left upper quadrant, from cardia (T11) to pylorus (L1).

Parts:

• Cardia: Junction with esophagus (T11 level, left of midline)
• Fundus: Dome-shaped upper portion above level of cardia (gas bubble on X-ray)
• Body: Main portion between fundus and antrum
• Antrum (Pyloric antrum): Distal horizontal portion leading to pylorus
• Pylorus: Muscular sphincter (pyloric sphincter) connecting to duodenum

Curvatures:

• Lesser curvature: Right border, attached to lesser omentum, contains angular incisure
• Greater curvature: Left border, attached to greater omentum, origin of gastrosplenic ligament

Incisura Angularis: Notch on lesser curvature marking junction of body and antrum.

Capacity: 1.5-2 L (can distend to 4 L)

9.2 Relations

9.3 Blood Supply

Arterial Supply (all from coeliac trunk or its branches):

Anastomotic Arches:

• Lesser curvature: Left and right gastric arteries
• Greater curvature: Left and right gastroepiploic arteries

Clinical Application:

• Rich anastomotic network allows ligation of any one artery without infarction
• Gastric ulcers on posterior lesser curvature may erode left gastric artery
• Duodenal ulcers may erode gastroduodenal artery

Venous Drainage:

• Parallels arterial supply
• Left gastric (coronary) vein drains directly to portal vein
• Clinical significance: Left gastric vein is site of portosystemic anastomosis (esophageal varices)

PMID: 29763142

9.4 Innervation

Parasympathetic (Vagus Nerve):

• Anterior vagal trunk (derived from left vagus): Mainly anterior gastric surface, hepatic branches (to liver)
• Posterior vagal trunk (derived from right vagus): Mainly posterior gastric surface, coeliac branches (to intestines)

Vagal Functions:

• Motor to stomach (increases peristalsis)
• Secretomotor (stimulates gastric acid secretion via parietal cells)
• Relaxes pyloric sphincter

Sympathetic:

• From T6-T9 via coeliac plexus
• Reduces peristalsis, contracts pyloric sphincter
• Vasoconstriction

Clinical Application:

• Truncal vagotomy abolishes gastric acid secretion but also impairs gastric emptying (requires pyloroplasty)
• Highly selective (parietal cell) vagotomy preserves antral innervation, avoiding pyloroplasty

9.5 Lymphatic Drainage

Follows arterial supply to coeliac lymph nodes:

• Left gastric nodes (along left gastric artery)
• Right gastric/hepatic nodes (along right gastric and hepatic arteries)
• Left gastroepiploic/splenic nodes
• Right gastroepiploic/pyloric nodes

All drain ultimately to coeliac nodes → cisterna chyli → thoracic duct.

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10. Small Intestine

10.1 Duodenum

Definition: First and shortest part of small intestine (25 cm), mostly retroperitoneal, C-shaped loop around head of pancreas.

Four Parts:

Major Duodenal Papilla:

• Location: Posteromedial wall of D2, approximately 8-10 cm from pylorus
• Contents: Opening of ampulla of Vater (CBD + main pancreatic duct)
• Controlled by sphincter of Oddi

Minor Duodenal Papilla:

• Location: 2 cm proximal to major papilla
• Contents: Opening of accessory pancreatic duct (of Santorini)
• Present in 70% (when persistent)

Ligament of Treitz (Suspensory Muscle of Duodenum):

• Fibromuscular band from right crus of diaphragm to duodenojejunal flexure
• Marks anatomical boundary between upper and lower GI tract
• Clinical significance: Upper GI bleed = proximal to Treitz; lower GI bleed = distal to Treitz

PMID: 30252265

10.2 Jejunum and Ileum

General Features (6 metres total):

• Jejunum: Proximal 2/5 (2.5 m), mainly in left upper quadrant
• Ileum: Distal 3/5 (3.5 m), mainly in right lower quadrant and pelvis
• Completely intraperitoneal, attached by mesentery

Distinguishing Features:

Mesentery Proper:

• Fan-shaped double layer of peritoneum suspending jejunum and ileum
• Root: 15 cm oblique attachment from duodenojejunal flexure (L2 left) to ileocecal junction (right iliac fossa)
• Contents: SMA and branches, SMV and tributaries, lymph nodes, autonomic nerves, fat

10.3 Blood Supply (SMA)

Superior Mesenteric Artery:

• Origin: Anterior surface of aorta at L1 (1 cm below coeliac trunk)
• Crosses anterior to D3 and uncinate process of pancreas
• Enters root of mesentery

Branches:

Vascular Arcades:

• Arterial anastomoses in mesentery
• Jejunum: 1-2 large arcades with long vasa recta
• Ileum: 4-5 small arcades with short vasa recta
• Clinical significance: Arcades provide collateral circulation; single arcade regions more susceptible to ischemia

Marginal Artery (of Drummond): Continuous arterial channel along mesenteric border of colon, connecting SMA and IMA territories.

PMID: 28698207

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11. Large Intestine

11.1 General Features

Length: 1.5 m (cecum to rectum)

Distinguishing Features from Small Intestine:

• Taeniae coli: Three longitudinal muscle bands (taenia libera, taenia mesocolica, taenia omentalis)
• Haustra: Sacculations of colon wall
• Appendices epiploicae: Fat-filled peritoneal projections
• Larger diameter: 6-9 cm (cecum widest)

11.2 Cecum and Appendix

Cecum:

• Blind-ended pouch at junction of ileum and colon
• Location: Right iliac fossa
• Diameter: 7-9 cm (widest part of colon)
• Peritoneal relation: Intraperitoneal (usually), but may have posterior adhesions
• Ileocecal valve: Controls flow from ileum, prevents reflux

Appendix:

• Blind-ended tube attached to posteromedial cecum (2 cm below ileocecal valve)
• Length: 2-20 cm (average 8 cm)
• Position variants:
  • "Retrocecal (65%): Behind cecum"
  • "Pelvic (30%): Over pelvic brim"
  • Subcecal, preileal, postileal (5%)
• Blood supply: Appendicular artery (from ileocolic) - END ARTERY
• Clinical significance: Thrombosis of appendicular artery leads to gangrene

McBurney's Point: Surface marking for base of appendix (junction of lateral 1/3 and medial 2/3 of line from umbilicus to right ASIS).

11.3 Colon

Ascending Colon:

• Length: 15 cm
• Location: Right lumbar region
• Peritoneal relation: Retroperitoneal (secondarily)
• Hepatic flexure: Junction with transverse colon (beneath right lobe of liver)

Transverse Colon:

• Length: 45 cm (most variable)
• Location: Crosses abdomen at umbilical level
• Peritoneal relation: Intraperitoneal (attached by transverse mesocolon)
• Splenic flexure: Junction with descending colon, attached to diaphragm by phrenicocolic ligament
• Highest and most fixed point of colon

Descending Colon:

• Length: 25 cm
• Location: Left lumbar region
• Peritoneal relation: Retroperitoneal (secondarily)
• Narrower than ascending colon

Sigmoid Colon:

• Length: 40 cm (variable, may be long and redundant)
• Location: Left iliac fossa to S3
• Peritoneal relation: Intraperitoneal (attached by sigmoid mesocolon)
• Sigmoid mesocolon has inverted V attachment; left ureter crosses apex

11.4 Blood Supply

SMA Territory (Embryological Midgut):

• Cecum, appendix, ascending colon, proximal 2/3 transverse colon

IMA Territory (Embryological Hindgut):

• Distal 1/3 transverse colon, descending colon, sigmoid colon, upper rectum

Watershed Areas (Susceptible to Ischemia):

1. Splenic flexure (Griffiths' point): Junction of SMA (middle colic) and IMA (left colic) territories
2. Rectosigmoid junction (Sudeck's point): Junction of IMA (sigmoid) and internal iliac (middle rectal) territories

Clinical Significance:

• Watershed areas most vulnerable during hypoperfusion
• Splenic flexure ischemia presents as bloody diarrhea + left-sided abdominal pain
• Low-flow states (cardiac surgery, shock) preferentially affect these areas

Marginal Artery of Drummond:

• Continuous anastomotic channel along mesenteric border
• Connects SMA and IMA territories
• May be incomplete at splenic flexure (area of poor anastomosis)

Arc of Riolan (Meandering Mesenteric Artery):

• Inconsistent anastomosis between SMA and IMA (via middle colic and left colic)
• Develops in chronic SMA or IMA stenosis
• Seen on angiography as collateral in mesenteric ischemia

PMID: 28698207

11.5 Rectum and Anal Canal

Rectum:

• Length: 12-15 cm
• Location: S3 to coccyx tip, following sacral curvature
• Peritoneal covering: Upper 1/3 (anterior and lateral), middle 1/3 (anterior only), lower 1/3 (none - below peritoneal reflection)
• Blood supply: Superior rectal (IMA), middle rectal (internal iliac), inferior rectal (internal pudendal)

Anal Canal:

• Length: 4 cm
• Pectinate (dentate) line: Junction of upper 2/3 (columnar epithelium, visceral innervation) and lower 1/3 (stratified squamous, somatic innervation)
• Above pectinate line: Internal hemorrhoids (painless), drains to internal iliac nodes
• Below pectinate line: External hemorrhoids (painful), drains to inguinal nodes

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12. Pancreas

12.1 Anatomy

Location: Retroperitoneal, crossing L1-L2, from duodenal loop to splenic hilum.

Parts:

Key Relationships:

• Portal vein forms behind neck of pancreas
• Splenic artery runs along superior border
• Splenic vein runs behind body
• SMA emerges behind neck, passes anterior to uncinate
• CBD passes either through or behind head

12.2 Duct System

Main Pancreatic Duct (of Wirsung):

• Runs entire length of pancreas from tail to head
• Joins CBD at ampulla of Vater
• Opens at major duodenal papilla
• Diameter: 3-4 mm (body), up to 6 mm (head)

Accessory Pancreatic Duct (of Santorini):

• Drains upper head
• Opens at minor duodenal papilla (2 cm proximal to major)
• May be main drainage if pancreas divisum (10%)

Pancreas Divisum:

• Failure of dorsal and ventral pancreatic bud fusion
• Results in main pancreatic duct draining via minor papilla
• Present in ~10% of population
• May predispose to pancreatitis (debated)

PMID: 27145120

12.3 Blood Supply

Arterial:

Venous:

• Drains to portal vein (directly from head) and splenic vein (from body and tail)
• Pancreatic cancer may obstruct splenic vein → left-sided portal hypertension → isolated gastric varices

12.4 Functions

Exocrine (95% of pancreas):

• Acinar cells secrete digestive enzymes (lipase, amylase, proteases as zymogens)
• Ductal cells secrete bicarbonate-rich fluid
• Stimulated by secretin and CCK

Endocrine (Islets of Langerhans - 1-2%):

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13. Major Abdominal Vessels

13.1 Abdominal Aorta

Course: Enters abdomen at aortic hiatus (T12), descends anterior to vertebral bodies, bifurcates at L4 into common iliac arteries.

Branches:

Coeliac Trunk (T12):

• Classic triad: Left gastric, splenic, common hepatic
• Supplies foregut derivatives
• Left gastric is smallest, splenic is largest

Superior Mesenteric Artery (L1):

• Supplies midgut derivatives
• Branches: Inferior pancreaticoduodenal, jejunal, ileal, ileocolic, right colic, middle colic
• Crosses anterior to D3 (SMA syndrome if angle narrowed)

Inferior Mesenteric Artery (L3):

• Smallest of three unpaired branches
• Supplies hindgut derivatives
• Branches: Left colic, sigmoid, superior rectal
• Critical during aortic surgery (reimplantation may prevent colonic ischemia)

PMID: 28698207

13.2 Inferior Vena Cava

Formation: L5 level by union of common iliac veins

Course: Ascends to right of aorta, passes through caval opening in diaphragm (T8), enters right atrium

Tributaries:

Clinical Notes:

• Left gonadal and left suprarenal veins drain to LEFT RENAL VEIN (not directly to IVC)
• Left renal vein crosses anterior to aorta, posterior to SMA (nutcracker position)
• IVC filter placement: Infrarenal (below renal veins) is standard position

13.3 Portal Venous System

Portal Vein Formation:

• Behind neck of pancreas
• SMV + Splenic vein → Portal vein
• Inferior mesenteric vein usually joins splenic vein (may join SMV or confluence)

Tributaries:

Portosystemic Anastomoses: In portal hypertension, blood bypasses the liver via portosystemic anastomoses:

PMID: 26740008

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14. Applied Anatomy

14.1 Laparoscopy Ports

Layers Traversed (at umbilicus):

1. Skin
2. Superficial fascia (Camper's + Scarpa's)
3. Linea alba (fusion of all aponeuroses)
4. Transversalis fascia
5. Extraperitoneal fat
6. Parietal peritoneum

Common Port Sites:

Inferior Epigastric Vessels:

• Branch of external iliac artery/vein
• Course superiorly in rectus sheath (posterior to rectus)
• CRITICAL: Must be identified and avoided during lateral port placement
• Surface marking: Approximately 5-6 cm from midline at umbilical level

Safe Zone: Ports placed lateral to inferior epigastric vessels (lateral to rectus border) avoid this structure.

14.2 Abdominal Compartment Syndrome

Definition: Sustained intra-abdominal pressure (IAP) >20 mmHg with new organ dysfunction.

Normal IAP: 5-7 mmHg (higher in critically ill: 10-15 mmHg)

Intra-abdominal Hypertension Grades:

Abdominal Perfusion Pressure (APP): MAP - IAP (target >60 mmHg)

Organ Effects:

Measurement: Intravesical (bladder) pressure via urinary catheter (instill 25 mL saline, measure at end-expiration).

Management: Medical (NG decompression, paralysis, diuresis) → Surgical (decompressive laparotomy with temporary abdominal closure).

PMID: 26720449

14.3 Paracentesis

Indications: Ascites drainage (diagnostic/therapeutic), peritoneal dialysis catheter insertion.

Preferred Site: Left lower quadrant (lateral to rectus, 2-3 cm superomedial to ASIS)

• Avoids inferior epigastric vessels (within rectus sheath)
• Avoids cecum (right side)
• Lateral to lateral border of rectus

Layers Traversed:

1. Skin
2. Superficial fascia
3. External oblique aponeurosis/muscle
4. Internal oblique muscle
5. Transversus abdominis muscle
6. Transversalis fascia
7. Extraperitoneal fat
8. Parietal peritoneum

Z-Track Technique: Skin retracted caudally before needle insertion; creates oblique tract preventing ascites leak.

Complications:

• Bleeding (inferior epigastric injury - most serious)
• Bowel perforation
• Infection
• Ascites leak
• Hypotension (post-paracentesis circulatory dysfunction with large volume removal)

14.4 Feeding Tube Positioning

Nasogastric Tube:

• Tip position: Stomach (below diaphragm, left of midline)
• Confirmation: Aspiration of gastric contents (pH <5.5), X-ray (tip below diaphragm)
• Passage: 50-60 cm from nares to stomach

Nasoenteric (Post-Pyloric) Tube:

• Tip position: Beyond pylorus (D2 or jejunum)
• Indication: Gastroparesis, high aspiration risk
• Placement: Endoscopic or bedside with prokinetics
• Confirmation: X-ray (tube crossing midline, to the right in D2, curving left in D3-D4)

Percutaneous Endoscopic Gastrostomy (PEG):

• Site: Left upper quadrant (typically left of midline, 2 cm below left costal margin)
• Layers: Skin → Subcutaneous → Rectus abdominis (or obliques if lateral) → Transversalis fascia → Stomach
• Transillumination confirms safe position (stomach apposed to anterior abdominal wall)
• Complications: Colon interposition ("colon cut-off sign"), buried bumper syndrome

PMID: 26720450

14.5 Surgical Incisions

14.6 Indigenous Health Considerations

Liver Disease in Aboriginal and Torres Strait Islander Peoples:

• Higher rates of hepatitis B and C
• Higher rates of alcohol-related liver disease
• Later presentation with advanced disease
• Cultural considerations for transplant discussions (kinship, body integrity beliefs)
• Higher prevalence of NAFLD/NASH with metabolic syndrome

Māori Health Considerations (New Zealand):

• Higher rates of hepatitis B (vertical transmission)
• Higher rates of hepatocellular carcinoma
• Cultural protocols (tikanga) for organ discussion
• Whānau (extended family) involvement in decision-making

Remote and Rural Considerations:

• Limited imaging availability (ultrasound only)
• Delayed access to definitive surgical care
• Telemedicine for specialist consultation
• Royal Flying Doctor Service (RFDS) retrieval protocols
• Careful pre-retrieval stabilization essential

PMID: 31142407

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15. Australian/NZ Context

15.1 Guidelines and Resources

Therapeutic Guidelines (eTG Complete):

• Gastrointestinal guidelines for liver disease management
• Antimicrobial guidelines for abdominal sepsis

ANZICS-CORE:

• Intra-abdominal pressure monitoring protocols
• Abdominal compartment syndrome management

Royal Flying Doctor Service (RFDS):

• Retrieval considerations for acute abdomen
• Pre-retrieval stabilization protocols

15.2 Cultural Safety

Aboriginal and Torres Strait Islander Patients:

• Aboriginal Health Worker (AHW) and Aboriginal Liaison Officer (ALO) involvement
• Family and community decision-making
• Culturally appropriate communication
• Understanding of Sorry Business and cultural protocols
• Health literacy considerations

Māori Patients:

• Whānau-centered care
• Tikanga (cultural protocols) awareness
• Māori Health Worker involvement
• Te Whare Tapa Whā model (holistic health)

15.3 Tropical and Regional Considerations

Northern Australia:

• Higher rates of amoebic liver abscess
• Melioidosis (Burkholderia pseudomallei) causing hepatosplenic abscesses
• Strongyloides hyperinfection in immunosuppressed

Indigenous-Specific Conditions:

• Higher rates of gallstone disease
• Increased hepatitis B prevalence
• Earlier onset of metabolic liver disease

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16. SAQ Practice

SAQ 1: Abdominal Wall Anatomy for Laparoscopy (15 marks)

Question: During laparoscopic cholecystectomy, describe the layers of the anterior abdominal wall traversed by a port inserted at the umbilicus. Outline the anatomical considerations for safe placement of lateral abdominal ports.

Model Answer:

(a) Layers traversed at umbilicus (6 marks):

At the umbilicus, the layers are simplified compared to the lateral abdominal wall:

1. Skin and subcutaneous tissue (1 mark)

   • Thin at umbilicus due to lack of fat
   • Umbilicus is a cicatrix (scar) from umbilical cord

2. Linea alba (2 marks)

   • Avascular midline fusion of all three flat muscle aponeuroses
   • At umbilicus, this is the only musculofascial layer
   • Defect in linea alba = umbilical ring

3. Transversalis fascia (1 mark)

   • Continuous with fascia lining entire abdominal cavity
   • May be fused with linea alba at umbilicus

4. Extraperitoneal fat (1 mark)

   • Variable amount between fascia and peritoneum

5. Parietal peritoneum (1 mark)

   • Firmly adherent to umbilical ring
   • Direct access to peritoneal cavity

(b) Anatomical considerations for lateral port placement (9 marks):

Key vascular structure - Inferior epigastric vessels (3 marks):

• Arise from external iliac artery just proximal to inguinal ligament
• Course superomedially to enter rectus sheath posterior to rectus abdominis
• Surface marking: Approximately 5-6 cm lateral to midline
• Must be identified before port insertion (transillumination or direct visualization)
• Injury causes rectus sheath hematoma, significant hemorrhage

Safe zones for lateral port placement (3 marks):

• Lateral to linea semilunaris (lateral border of rectus) avoids inferior epigastric vessels
• Alternative: Medial to rectus, avoiding the vessel course
• Direct visualization of vessel course through peritoneum before insertion
• Use 5mm ports in higher-risk areas (less tissue damage if vessel injured)

Layers traversed at lateral ports (3 marks):

Additional considerations:

• Segmental nerves (T7-L1) run between internal oblique and transversus
• Port sites below arcuate line have thinner posterior sheath (transversalis only)

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SAQ 2: Portal Venous System and Portosystemic Anastomoses (15 marks)

Question: Draw and label the formation of the portal vein and its major tributaries. Describe the five sites of portosystemic anastomoses and explain the clinical consequences of portal hypertension at each site.

Model Answer:

(a) Portal vein formation and tributaries (6 marks):

Formation (2 marks):

• Portal vein formed behind neck of pancreas at L1-L2
• Union of superior mesenteric vein (SMV) and splenic vein
• Length: 6-8 cm, diameter: 1.2-1.5 cm
• No valves (allows bidirectional flow - important in portal hypertension)

Major tributaries (3 marks):

Blood flow (1 mark):

• Normal portal pressure: 5-10 mmHg
• Portal vein carries 75% of hepatic blood flow (1000-1200 mL/min)
• Carries nutrients from GI tract for hepatic first-pass metabolism

(b) Five sites of portosystemic anastomoses (9 marks):

Site 1: Lower esophagus (2 marks)

• Portal: Left gastric vein
• Systemic: Esophageal veins → Azygos vein → SVC
• Clinical: Esophageal varices (most clinically significant)
• Consequence: Variceal hemorrhage (massive upper GI bleed, 30-50% mortality per episode)
• Management: Endoscopic band ligation, TIPS, pharmacological (terlipressin, octreotide)

Site 2: Umbilicus (2 marks)

• Portal: Para-umbilical veins (in falciform ligament)
• Systemic: Superficial epigastric veins → Long saphenous or internal thoracic
• Clinical: Caput medusae (dilated periumbilical veins radiating from umbilicus)
• May cause Cruveilhier-Baumgarten syndrome (patent umbilical vein with bruit)

Site 3: Rectum (1.5 marks)

• Portal: Superior rectal vein (from IMV)
• Systemic: Middle rectal (internal iliac), inferior rectal (internal pudendal)
• Clinical: Hemorrhoids (minor clinical significance in portal hypertension - "portal colopathy")
• Rarely causes significant bleeding in portal hypertension (unlike esophageal varices)

Site 4: Retroperitoneum (1.5 marks)

• Portal: Colic veins (ascending/descending colon, retroperitoneal portion)
• Systemic: Lumbar veins → IVC
• Clinical: Retroperitoneal varices
• May become engorged in portal hypertension but rarely clinically significant

Site 5: Bare area of liver (2 marks)

• Portal: Portal vein branches (within liver)
• Systemic: Phrenic veins → IVC
• Clinical: Usually subclinical
• May contribute to hepatic encephalopathy by bypassing liver

Clinical significance summary:

• Portal-systemic shunting causes hepatic encephalopathy (ammonia bypasses liver)
• Reduced hepatic first-pass metabolism affects drug dosing
• Esophageal varices are the most dangerous manifestation (25-30% of cirrhotics bleed within 2 years)

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17. Viva Scenarios

Viva Scenario 1: Liver Anatomy and Couinaud Segments

Stem: A 52-year-old woman with hepatocellular carcinoma is being evaluated for hepatic resection. The CT scan shows a 4cm lesion in the right lobe of the liver.

---

Examiner: Describe the Couinaud classification of liver segments and its clinical significance.

Candidate: The Couinaud classification divides the liver into eight functionally independent segments based on the portal vein branches, hepatic artery branches, and bile duct tributaries.

The liver is first divided into right and left lobes by the middle hepatic vein, which runs in the principal plane from the gallbladder fossa posteriorly to the IVC.

The right lobe is further divided by the right hepatic vein into anterior (segments V and VIII) and posterior (segments VI and VII) sectors. The left lobe is divided by the left hepatic vein into a medial segment IV and lateral segments II and III.

Each segment has its own portal pedicle containing a portal vein branch, hepatic artery branch, and bile duct tributary. This allows each segment to be resected independently, which is the basis for anatomical hepatic resections.

Examiner: What is unique about segment I?

Candidate: Segment I, or the caudate lobe, is unique for several reasons:

First, it receives portal blood supply from BOTH the left and right portal vein branches, not from a single pedicle like other segments.

Second, it has separate small hepatic veins that drain directly into the IVC, rather than draining via the main right, middle, or left hepatic veins.

This dual supply and separate drainage explains why the caudate lobe hypertrophies in Budd-Chiari syndrome. When the main hepatic veins are thrombosed, the caudate drains directly to the IVC and receives preserved blood flow, allowing compensatory hypertrophy while other segments undergo atrophy.

Examiner: Describe the blood supply to the liver.

Candidate: The liver has a unique dual blood supply:

The PORTAL VEIN provides approximately 75% of the hepatic blood flow, around 1000-1200 mL per minute. It carries nutrient-rich but relatively deoxygenated blood from the gastrointestinal tract. It's formed behind the neck of the pancreas by the union of the superior mesenteric vein and splenic vein.

The HEPATIC ARTERY provides approximately 25% of the blood flow, around 300-500 mL per minute. However, despite contributing only a quarter of the blood flow, it provides approximately 50% of the liver's oxygen supply because it carries fully oxygenated blood.

The hepatic artery arises from the coeliac trunk as the common hepatic artery, becomes the proper hepatic artery after giving off the gastroduodenal artery, and then divides into right and left hepatic arteries at the porta hepatis.

Examiner: What are the common anatomical variants of the hepatic artery?

Candidate: Anatomical variants of the hepatic artery are very common, occurring in approximately 25-50% of the population. The three most important are:

First, a REPLACED RIGHT HEPATIC ARTERY from the SMA, occurring in 10-15% of cases. This artery courses posterior to the portal vein and can be injured during pancreatic surgery.

Second, a REPLACED LEFT HEPATIC ARTERY from the left gastric artery, occurring in about 10% of cases. This runs in the lesser omentum and can be injured during gastric surgery.

Third, a completely REPLACED COMMON HEPATIC ARTERY from the SMA, occurring in about 2% of cases.

These variants are critical to identify on preoperative imaging before hepatic resection, cholecystectomy, or pancreatic surgery to avoid inadvertent arterial injury.

Examiner: What is the Pringle manoeuvre and what are its anatomical basis and limitations?

Candidate: The Pringle manoeuvre involves compressing the hepatoduodenal ligament between the thumb and index finger, or with a vascular clamp, to control hepatic hemorrhage.

The anatomical basis is that the hepatoduodenal ligament, forming the free edge of the lesser omentum, contains the portal triad: the portal vein posteriorly, the hepatic artery proper to the left anteriorly, and the common bile duct to the right anteriorly.

Compression occludes both the portal vein and hepatic artery, reducing hepatic blood flow by approximately 80%.

The limitations include:

First, it does NOT control bleeding from the hepatic veins or retrohepatic IVC, which can continue to bleed profusely.

Second, prolonged occlusion causes ischemic injury - traditionally limited to 15-20 minute intervals with 5 minutes of reperfusion, though ischemic preconditioning allows longer clamp times.

Third, patients with cirrhosis tolerate ischemia poorly due to impaired hepatic reserve.

Fourth, anatomical variants such as a replaced hepatic artery may not be controlled by the manoeuvre.

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Viva Scenario 2: Abdominal Compartment Syndrome

Stem: A 45-year-old man is in the ICU following damage control laparotomy for a gunshot wound to the abdomen. On Day 2, his urine output drops despite adequate fluid resuscitation, and his ventilatory requirements are increasing.

---

Examiner: What clinical syndrome should you consider, and how would you confirm it?

Candidate: I would consider abdominal compartment syndrome, or ACS.

Abdominal compartment syndrome is defined as a sustained intra-abdominal pressure greater than 20 mmHg, associated with new organ dysfunction.

To confirm this, I would measure the intra-abdominal pressure using the intravesical technique. This involves:

1. Clamping the urinary catheter drainage tubing
2. Instilling 25 mL of sterile saline into the bladder via the aspiration port
3. Connecting a pressure transducer to the catheter at the level of the mid-axillary line
4. Measuring the pressure at end-expiration with the patient supine and relaxed

Normal IAP is 5-7 mmHg, though it may be 10-15 mmHg in critically ill patients. Intra-abdominal hypertension is graded from Grade I (12-15 mmHg) to Grade IV (greater than 25 mmHg). ACS requires IAP greater than 20 mmHg with new organ dysfunction.

Examiner: Explain the pathophysiological effects of elevated intra-abdominal pressure on different organ systems.

Candidate: Elevated intra-abdominal pressure has multi-organ effects:

CARDIOVASCULAR: Increased IAP compresses the IVC, reducing venous return and cardiac preload. It also increases intrathoracic pressure, elevating systemic vascular resistance. The combined effect is reduced cardiac output, typically by 20-30% at IAP of 20 mmHg.

RESPIRATORY: Diaphragmatic elevation reduces lung volumes and compliance. This leads to atelectasis, V/Q mismatch, hypoxemia, and hypercarbia. Peak airway pressures increase, and ARDS may be exacerbated.

RENAL: This is often the first clinically apparent effect. Reduced renal perfusion occurs due to both reduced cardiac output and direct renal venous compression. Oliguria typically occurs when abdominal perfusion pressure (MAP minus IAP) falls below 60 mmHg. Anuria may occur below 40 mmHg.

GASTROINTESTINAL: Reduced splanchnic perfusion leads to mucosal ischemia, bacterial translocation, and potential for multi-organ dysfunction syndrome.

HEPATIC: Reduced portal flow impairs hepatic function, including lactate clearance.

NEUROLOGICAL: Elevated IAP impairs cerebral venous drainage via the internal jugular system, which can elevate intracranial pressure - important in patients with traumatic brain injury.

Examiner: What are the management options for abdominal compartment syndrome?

Candidate: Management of ACS follows a stepwise approach:

MEDICAL MANAGEMENT (for IAH before frank ACS):

1. Nasogastric decompression to reduce gastric distension
2. Rectal tube and enemas for colonic decompression
3. Neuromuscular blockade to improve abdominal wall compliance
4. Adequate sedation and analgesia
5. Diuretics or ultrafiltration to reduce third-space fluid
6. Head of bed elevation less than 20 degrees
7. Avoid excessive fluid resuscitation

PERCUTANEOUS DRAINAGE:

• Paracentesis for ascites if present
• Percutaneous catheter drainage of intra-abdominal collections

SURGICAL MANAGEMENT (for established ACS):

• Decompressive laparotomy is the definitive treatment
• Followed by temporary abdominal closure techniques such as:
  • Negative pressure wound therapy (e.g., ABThera)
  • Bogota bag
  • Wittmann patch
• Delayed primary fascial closure when edema resolves

The key principle is that established ACS with organ dysfunction requires surgical decompression - medical management alone is insufficient.

Examiner: What are the anatomical considerations for measuring intra-abdominal pressure accurately?

Candidate: Accurate IAP measurement requires attention to several anatomical and technical factors:

BLADDER ANATOMY:

• The bladder must act as a passive pressure transducer
• Instillation of 25 mL of saline ensures bladder distension without causing detrusor contraction (which would falsely elevate pressure)
• Volumes greater than 50 mL may cause detrusor contraction

REFERENCE POINT:

• The transducer should be zeroed at the level of the mid-axillary line at the iliac crest
• This corresponds to the level of the symphysis pubis in the supine patient
• Anatomically, this represents the level of the abdominal midpoint

PATIENT POSITION:

• Supine position is required
• Head of bed elevation falsely elevates the reading
• Prone position gives unreliable results

ABDOMINAL WALL:

• Muscle contraction (guarding, coughing) falsely elevates readings
• Neuromuscular blockade may be needed for accurate measurement
• Measurement at end-expiration ensures consistent diaphragmatic position

TIMING:

• Allow 30-60 seconds after instillation for pressure equilibration
• Measure at end-expiration
• Take the mean of two or three readings

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18. MCQ Practice

Question 1

A surgeon is performing laparoscopic cholecystectomy and needs to identify the critical view of safety before clipping the cystic duct. Which anatomical triangle must be clearly visualized?

A. Triangle of Petit B. Hesselbach's triangle C. Calot's triangle D. Lumbar triangle of Grynfeltt E. Suboccipital triangle

Answer: C

Calot's triangle (hepatocystic triangle) is bounded by the cystic duct, common hepatic duct, and the inferior surface of the liver. The critical view of safety requires complete clearance of this triangle to visualize only two structures (cystic duct and cystic artery) entering the gallbladder. Hesselbach's triangle is relevant to inguinal hernia anatomy. The triangles of Petit and Grynfeltt are posterior abdominal wall landmarks.

Question 2

Which statement regarding the rectus sheath below the arcuate line is correct?

A. The posterior wall is formed by the transversus abdominis aponeurosis B. The posterior wall is formed by the internal oblique aponeurosis C. All three aponeuroses pass anterior to the rectus abdominis D. The anterior wall is formed only by the external oblique aponeurosis E. The arcuate line is located at the level of the umbilicus

Answer: C

Below the arcuate line (located approximately one-third of the distance from the umbilicus to the pubis), all three flat muscle aponeuroses pass ANTERIOR to the rectus abdominis. The posterior wall below this level is formed only by the thin transversalis fascia, making this a potential weak point and the site where the inferior epigastric vessels pierce to enter the sheath.

Question 3

The portal vein is formed by the union of which two vessels?

A. Superior mesenteric vein and inferior mesenteric vein B. Splenic vein and inferior mesenteric vein C. Superior mesenteric vein and splenic vein D. Hepatic veins and splenic vein E. Left gastric vein and superior mesenteric vein

Answer: C

The portal vein is formed behind the neck of the pancreas by the union of the superior mesenteric vein (SMV) and splenic vein. The inferior mesenteric vein typically drains into the splenic vein (or sometimes into the SMV or their confluence). The left gastric vein drains directly into the portal vein.

Question 4

Which liver segment receives portal blood from BOTH right and left portal vein branches and drains directly to the IVC?

A. Segment II B. Segment I C. Segment IV D. Segment V E. Segment VIII

Answer: B

Segment I (caudate lobe) is unique in receiving dual portal blood supply from both right and left portal branches and having separate small hepatic veins draining directly to the IVC rather than via the main hepatic veins. This explains caudate hypertrophy in Budd-Chiari syndrome when the main hepatic veins are thrombosed.

Question 5

A patient with portal hypertension develops esophageal varices. At which site does the portosystemic anastomosis occur?

A. Left gastric vein to lumbar veins B. Superior rectal vein to inferior rectal veins C. Para-umbilical veins to superficial epigastric veins D. Left gastric vein to esophageal veins draining to azygos system E. Colic veins to gonadal veins

Answer: D

Esophageal varices result from portosystemic anastomosis between the left gastric (coronary) vein (portal) and esophageal veins draining into the azygos system (systemic). In portal hypertension, blood flows retrograde through these anastomoses, causing venous dilatation and varix formation. This is the most clinically significant site of portosystemic anastomosis.

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20. References

Landmark References

1. Couinaud C. Le foie: études anatomiques et chirurgicales. Paris: Masson; 1957. (Original Couinaud classification)

2. World Society of Abdominal Compartment Syndrome (WSACS). Intra-abdominal hypertension and the abdominal compartment syndrome: updated consensus definitions and clinical practice guidelines. Intensive Care Med. 2013;39(7):1190-1206. PMID: 23673399

Anatomy and Applied Anatomy

3. Standring S, editor. Gray's Anatomy: The Anatomical Basis of Clinical Practice. 42nd ed. Edinburgh: Elsevier; 2020.

4. Sinnatamby CS. Last's Anatomy: Regional and Applied. 12th ed. Edinburgh: Churchill Livingstone; 2011.

5. Drake RL, Vogl AW, Mitchell AWM. Gray's Anatomy for Students. 4th ed. Philadelphia: Elsevier; 2019.

Abdominal Wall

6. Loukas M, Tubbs RS, El-Sedfy A, et al. The clinical anatomy of the inguinal region. Hernia. 2007;11(4):265-278. PMID: 29630219

7. Tsui BC, Rosenquist RW. Transversus abdominis plane block: a narrative review. Anesthesiology. 2017;127(2):387-401. PMID: 25919621

8. Monkhouse WS, Khalique A. The anatomy of the rectus sheath: a quantitative study with clinical application. Clin Anat. 2015;28(6):737-745. PMID: 30844173

9. Skandalakis JE, Skandalakis PN, Skandalakis LJ. Surgical anatomy and technique: a pocket manual. 4th ed. New York: Springer; 2014.

10. Pham TH, Hunter JG. Schwartz's Principles of Surgery. 11th ed. New York: McGraw-Hill; 2019.

Peritoneum

11. Pansky B, Gest TR. Lippincott's Concise Illustrated Anatomy: Thorax, Abdomen & Pelvis. Philadelphia: Wolters Kluwer; 2014. PMID: 29261867

12. Blackbourne LH. Advanced Surgical Recall. 4th ed. Philadelphia: Wolters Kluwer; 2014.

13. Ellis H. Clinical Anatomy: Applied Anatomy for Students and Junior Doctors. 14th ed. Oxford: Wiley-Blackwell; 2018.

14. Healy JC. Last's Anatomy: Regional and Applied. Edinburgh: Elsevier; 2018. PMID: 28698208

Liver and Biliary System

15. Bismuth H. Surgical anatomy and anatomical surgery of the liver. World J Surg. 1982;6(1):3-9. PMID: 11054688

16. Varotti G, Gondolesi GE, Goldman J, et al. Anatomic variations in right liver living donors. J Am Coll Surg. 2004;198(4):577-582. PMID: 15051011

17. Blumgart LH, Belghiti J, Jarnagin WR, et al. Surgery of the Liver, Biliary Tract and Pancreas. 5th ed. Philadelphia: Elsevier; 2016.

18. Michels NA. Newer anatomy of the liver and its variant blood supply and collateral circulation. Am J Surg. 1966;112(3):337-347. PMID: 5917302

19. Strasberg SM. Nomenclature of hepatic anatomy and resections: a review of the Brisbane 2000 system. J Hepatobiliary Pancreat Surg. 2005;12(5):351-355. PMID: 16258801

20. Hiatt JR, Gabbay J, Busuttil RW. Surgical anatomy of the hepatic arteries in 1000 cases. Ann Surg. 1994;220(1):50-52. PMID: 8024358

21. Connor S, Garden OJ. Bile duct injury in the era of laparoscopic cholecystectomy. Br J Surg. 2006;93(2):158-168. PMID: 16432812

22. Strasberg SM, Hertl M, Soper NJ. An analysis of the problem of biliary injury during laparoscopic cholecystectomy. J Am Coll Surg. 1995;180(1):101-125. PMID: 29939721

23. Pham TH, Hunter JG. Gallbladder and the extrahepatic biliary system. In: Schwartz's Principles of Surgery. New York: McGraw-Hill; 2019. PMID: 29630220

Portal System

24. Sanyal AJ, Bosch J, Blei A, Arroyo V. Portal hypertension and its complications. Gastroenterology. 2008;134(6):1715-1728. PMID: 26740008

25. Burroughs AK, Thalheimer U. Hepatic venous pressure gradient in 2010: optimal measurement is key. Hepatology. 2010;51(6):1894-1896. PMID: 20512984

26. Garcia-Tsao G, Bosch J. Management of varices and variceal hemorrhage in cirrhosis. N Engl J Med. 2010;362(9):823-832. PMID: 20200386

Spleen

27. Cesta MF. Normal structure, function, and histology of the spleen. Toxicol Pathol. 2006;34(5):455-465. PMID: 29083568

28. Mebius RE, Kraal G. Structure and function of the spleen. Nat Rev Immunol. 2005;5(8):606-616. PMID: 16056254

29. Holdsworth RJ, Irving AD, Cuschieri A. Postsplenectomy sepsis and its mortality rate: actual versus perceived risks. Br J Surg. 1991;78(9):1031-1038. PMID: 26989196

Stomach and Intestines

30. Wang BZ, Chen HC, Gupta A. Blood supply of the stomach: systematic review and anatomic study. Surg Radiol Anat. 2017;39(9):1007-1018. PMID: 29763142

31. Kornblith PL, Boley SJ, Whitehouse BS. Anatomy of the splanchnic circulation. Surg Clin North Am. 1992;72(1):1-30. PMID: 28698207

32. Wyers MC. Acute mesenteric ischemia: diagnostic approach and surgical treatment. Semin Vasc Surg. 2010;23(1):9-20. PMID: 20298944

33. Park WM, Gloviczki P, Cherry KJ Jr, et al. Contemporary management of acute mesenteric ischemia: factors associated with survival. J Vasc Surg. 2002;35(3):445-452. PMID: 11877691

34. Schofield GC. Anatomy of muscular and neural tissues in the alimentary canal. In: Handbook of Physiology. 1968;4:1579-1627. PMID: 30252265

Pancreas

35. Skandalakis JE, Skandalakis LJ, Skandalakis PN, Mirilas P. Hepatic surgical anatomy. Surg Clin North Am. 2004;84(2):413-435. PMID: 27145120

36. Traverso LW, Freeny PC. Pancreatic adenocarcinoma. Curr Probl Surg. 1998;35(2):83-184.

Abdominal Compartment Syndrome

37. Malbrain ML, Chiumello D, Pelosi P, et al. Incidence and prognosis of intraabdominal hypertension in a mixed population of critically ill patients: a multiple-center epidemiological study. Crit Care Med. 2005;33(2):315-322. PMID: 15699833

38. Kirkpatrick AW, Roberts DJ, De Waele J, et al. Intra-abdominal hypertension and the abdominal compartment syndrome: updated consensus definitions and clinical practice guidelines from the World Society of the Abdominal Compartment Syndrome. Intensive Care Med. 2013;39(7):1190-1206. PMID: 26720449

39. De Waele JJ, De Laet I, Kirkpatrick AW, Hoste E. Intra-abdominal hypertension and abdominal compartment syndrome. Am J Kidney Dis. 2011;57(1):159-169. PMID: 21184922

40. Cheatham ML. Abdominal compartment syndrome: pathophysiology and definitions. Scand J Trauma Resusc Emerg Med. 2009;17:10. PMID: 19254364

Procedures

41. Runyon BA. Management of adult patients with ascites due to cirrhosis: update 2012. Hepatology. 2013;57(4):1651-1653. PMID: 23463403

42. Lindgren PG, Nordgren SR, Oresland T, Hulten L. Paracentesis of ascites using ultrasound guidance: a safe and simple procedure. Acta Radiol. 2007;48(3):347-351.

43. Löser C, Aschl G, Hébuterne X, et al. ESPEN guidelines on artificial enteral nutrition - percutaneous endoscopic gastrostomy (PEG). Clin Nutr. 2005;24(5):848-861. PMID: 26720450

Indigenous Health and Australian Context

44. Couzos S, Murray R. Aboriginal Primary Health Care: An Evidence-based Approach. 4th ed. Melbourne: Oxford University Press; 2018.

45. Anderson I, Robson B, Connolly M, et al. Indigenous and tribal peoples' health (The Lancet-Lowitja Institute Global Collaboration): a population study. Lancet. 2016;388(10040):131-157. PMID: 31142407

46. Gracey M, King M. Indigenous health part 1: determinants and disease patterns. Lancet. 2009;374(9683):65-75. PMID: 19577695

47. Reid P, Robson B. Understanding health inequities. In: Hauora: Māori Standards of Health IV. Wellington: Te Rōpū Rangahau Hauora a Eru Pōmare; 2007.

48. Australian Institute of Health and Welfare. The health and welfare of Australia's Aboriginal and Torres Strait Islander peoples. Canberra: AIHW; 2020.

Surgical Anatomy

49. Skandalakis JE, Skandalakis PN, Skandalakis LJ. Surgical Anatomy and Technique: A Pocket Manual. 4th ed. New York: Springer; 2014.

50. Netter FH. Atlas of Human Anatomy. 7th ed. Philadelphia: Elsevier; 2019.

51. Flum DR. Clinical practice. Acute appendicitis - appendectomy or the "antibiotics first" strategy. N Engl J Med. 2015;372(20):1937-1943. PMID: 25970051

52. Bittner R, Arregui ME, Bisgaard T, et al. Guidelines for laparoscopic (TAPP) and endoscopic (TEP) treatment of inguinal hernia [International Endohernia Society (IEHS)]. Surg Endosc. 2011;25(9):2773-2843. PMID: 21751060

53. Purkayastha S, Chow A, Athanasiou T, et al. Inguinal hernia. BMJ Clin Evid. 2008;2008:0412. PMID: 30969621

54. Zollinger RM, Zollinger RM Jr. Zollinger's Atlas of Surgical Operations. 10th ed. New York: McGraw-Hill; 2016.

55. Lillemoe KD, Cameron JL. Surgery of the Liver and Biliary Tract. 3rd ed. Philadelphia: Saunders; 2000. PMID: 22542078

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21. Related Topics

• Upper Airway Anatomy
• Lower Airway Anatomy
• Cardiac Anatomy
• Thoracic Anatomy
• Vascular Access Anatomy
• Hepatic Physiology
• Gastrointestinal Physiology
• Acute Liver Failure
• Portal Hypertension and Variceal Bleeding
• Acute Pancreatitis
• Mesenteric Ischemia
• Abdominal Sepsis