Anatomy of the Abdominal Cavity

Course Information

• Course Title: Sectional Anatomy Abdomen
• Course Code: MIT324
• College: Al-Ghad International College for Applied Medical Sciences
• Department: Radiological Sciences Department
• Week Numbers: 9 & 10

Objectives

• Students will be able to locate and identify anatomical structures within the abdomen on cadaver sections and CT/MR images.
• Students will be able to describe the 2-D and 3-D relationships of anatomical structures.
• Students will be able to distinguish between arterial and venous anatomy of the abdominal region.
• Students will be able to classify the various sections of the abdominal anatomical regions and associated parts.

Contents

• Abdomen
  • Major organs and their accessories
  • Vasculature
  • Diaphragm

The Abdomen

• The abdominal cavity houses many critical structures with diverse functions.
• Cross-sectional imaging is essential for visualizing these organs and body systems.

Abdominal Cavity

• The region between the diaphragm and sacral promontory.
• Contains the liver, gallbladder, biliary system, pancreas, spleen, adrenal glands, kidneys, ureters, stomach, intestines, and vascular structures.

Contents of the Abdominal Cavity

• Images show the liver, gallbladder, pancreas, stomach, large intestine, and small intestine. (Diagram included)

Peritoneum

• The abdominal cavity walls are lined with a thin, serous membrane called the peritoneum.
• It is divided into a parietal layer and a visceral layer.
• The parietal layer lines the abdominal wall, and the visceral layer covers the organs within the peritoneal cavity (liver, gallbladder, spleen, stomach, most of the intestines).

Axial CT of Abdomen and Peritoneal Spaces

• Images of the abdomen and peritoneal spaces are provided (Image included).
• Structures like the anterior subphrenic space, gallbladder, duodenum, liver, lesser sac, pancreas, superior mesenteric artery, and right subhepatic space are visible. (Image included)

Axial MR Scan of Peritoneal and Retroperitoneal Structures

• Images show peritoneal and retroperitoneal structures separated by dotted lines. (Image included)
• Structures like the aorta, peritoneum, inferior vena cava, pancreas, left kidney, spleen, and stomach are visible. (Image included)

Axial CT Scan of Peritoneal and Retroperitoneal Structures

• Images depicting peritoneal and retroperitoneal structures separated by dotted lines are provided. (Image included)
• Structures include the portal vein, stomach, pancreas, spleen, peritoneum, inferior vena cava, aorta, and left kidney are displayed. (Image included)

Axial MR Scan of Retroperitoneum

• Images showcasing the retroperitoneum (posterior to dotted line) are provided. (Image included)

Retroperitoneal Spaces

• Pararenal spaces
• Perirenal space

Axial View of Retroperitoneal Spaces

• A diagram outlining para-renal and peri-renal spaces with important structures like the liver, right kidney, anterior para-renal space, posterior para-renal space, stomach, pancreas, spleen, descending colon, and left kidney are presented. (Image included)

Axial, T1-weighted MRI of Abdomen with Kidneys and Para Renal Spaces

• MRI images showing kidneys and renal spaces, including posterior para-renal, anterior para-renal, and peri-renal spaces are given (with labels). (Image included)

Coronary T2-weighted MRI of Perirenal Spaces

• MRI images of perirenal spaces are included with labels for right and left perirenal spaces, renal fascia, psoas muscle, posterior para-renal space. (Image included)

Abdominal Regions

• Right Hypochondriac
• Epigastric
• Left Hypochondriac
• Right Lumbar
• Umbilical
• Left Lumbar
• Right Iliac
• Hypogastric
• Left Iliac

Abdominal Regions (Description)

• Right and left hypochondriac regions: on either side of the epigastric region, containing diaphragm, part of kidneys, liver, spleen, and pancreas.
• Epigastric region: superior to the umbilical region, containing mainly pancreas, stomach, liver, inferior vena cava, abdominal aorta, and duodenum.
• Right and left lumbar regions: on either side of the umbilical region, containing parts of the large and small intestines, and kidneys.
• Umbilical region: area around the umbilicus, containing sections of the large and small intestines, inferior vena cava, and abdominal aorta.
• Right and left iliac regions: on either side of the hypogastric region, containing parts of the large and small intestines.
• Hypogastric region: inferior to the umbilical region, containing parts of the sigmoid colon, urinary bladder, ureters, uterus (in women), and portions of the small intestines.

Liver

• Largest organ in the abdomen, usually positioned in the right upper quadrant.
• Divided into lobes (left, right, caudate, quadrate).

Spleen

• Largest lymphatic organ. Located posterior to the stomach, in the left upper quadrant of the abdomen.

Gallbladder

• Pear-shaped, located in a fossa on the antero-inferior portion of the right lobe of the liver.

Pancreas

• Long, narrow organ located behind the stomach, extending transversely from the duodenum toward the spleen.

Adrenal Gland

• Pyramidal-shaped, sits on the upper border of each kidney.
• The right gland is usually lower and more medial than the left.

Urinary System

• Includes kidneys, ureters, and urinary bladder.
• Kidneys are positioned on each side of the spine between T12-L4 along the posterior abdominal wall.
• Left kidney is often slightly higher than the right.

Stomach

• Located under the left dome of the diaphragm.
• Superior portion connects to the esophagus at the cardiac orifice (T10).

Intestine

• Small intestine: loops averaging 6-7 m in length, divided into duodenum, jejunum, and ileum.
• Large intestine: inferior to the stomach and liver, enclosing the small intestine. Parts include cecum, colon (ascending, transverse, descending, sigmoid), and rectum.

Abdominal Aorta and Branches

• Unpaired branches: celiac trunk, superior, and inferior mesenteric arteries.
• Paired branches: suprarenal, renal, and gonadal arteries.

Inferior Vena Cava and Tributaries

• Formed by the union of common iliac veins at the L5 level.
• Receives tributaries throughout its course in the abdomen, including lumbar, right gonadal, and hepatic veins.

Diaphragm

• Dome-shaped muscle separating the thoracic cavity from the abdominal cavity.
• Openings include aortic (T12), caval (T8), and esophageal (T10) openings.

CT Abdominal Region (Various Levels)

• Various CT images of the abdomen at different levels (L1, L2, L3, L4, lower L5) are provided with corresponding anatomical structures labelled.

MRI

• Detailed MRI images of the abdominal structures are displayed

Gall Bladder and Biliary System

• Structures of the gall bladder and biliary system (right/left hepatic ducts, common hepatic duct, common bile duct, pancreatic duct, sphincter of Oddi, C loop of duodenum) are identified in images.

Additional Venous Structures (in MRI)

• MRI images detailing the hepatic vein, inferior vena cava, right/left hepatic veins, diaphragm, right/left lobes of the liver, fundus of the stomach, spleen, thoracic aorta, spinal cord.

Additional Structures (in MRI)

• Detailed view of the left branch/right branch of the portal vein, caudate lobe, body of stomach, transverse colon, splenic artery/flexures, tail of the pancreas, right/left kidneys. right crus of the diaphragm, spinal cord, body of the pancreas, splenic vein, descending colon.

Additional Structures (in MRI)

• Images of the head of pancreas, left lobe of liver, pyloric part of the stomach, transverse colon, right lobe of the liver, right kidney, psoas muscle.

Additional Structures (in MRI)

• Detailed images with labeled structures like lungs, right lobe of liver, right kidney, cauda equina, spleen, psoas muscle, sacroiliac joint.

Additional Structures (in MRI)

• Detailed images (with labels) showing the lungs, diaphragm, right lobe of the liver, right kidney, intervertebral disc, spleen, minor calyx, vertebral body, psoas muscle.

Additional Structures (in MRI)

• Images and labels for lungs, diaphragm, right lobe of liver, heart, fundus of the stomach, left lobe of liver, gallbladder, duodenum, superior mesenteric vein.

Additional Structures (in MRI)

• Images and labels on transverse section of the abdomen: lungs, right lobe of liver, body of the stomach.

Additional Structures (in MRI)

• Images and labels for transverse section of the abdomen: lungs, right lobe of liver, body of the stomach, small bowels.