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Surgical Anatomy of the Abdomen

The abdominal cavity has a complex and intricate anatomy. A physician must know in which area of the abdomen every major structure is located to understand the clinical presentation of abdominal pathologies and/or in trauma situations to estimate which organs are most likely injured. The general surgeon, especially in emergency situations, uses this knowledge to execute the most advantageous surgical approach for a particular situation.

Last updated: Jul 9, 2024

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

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Surface Anatomy of the Abdomen

Boundaries

Superior:

  • Xiphoid process Xiphoid process Chest Wall: Anatomy
  • Costal cartilages of the 7th–10th ribs Ribs A set of twelve curved bones which connect to the vertebral column posteriorly, and terminate anteriorly as costal cartilage. Together, they form a protective cage around the internal thoracic organs. Chest Wall: Anatomy

Inferior:

Lateral: 

  • Superior: inferior aspect of the 10th rib
  • Inferior: iliac crest

Landmarks

Superficial anatomical landmarks abdomen

Superficial anatomical landmarks of the abdomen

Image by Lecturio. License: CC BY-NC-SA 4.0

Lines and planes

The following divide the abdomen into its 9 regions:

Regions of the abdomen

Dermatomes Dermatomes Spinal Cord: Anatomy

Dermatomes of the thorax, abdomen, and pelvis

Dermatomes of the thorax, abdomen, and pelvis

Image by Lecturio. License:

Abdominal Wall

Layers

  • Skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions
  • Superficial fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis ( subcutaneous tissue Subcutaneous tissue Loose connective tissue lying under the dermis, which binds skin loosely to subjacent tissues. It may contain a pad of adipocytes, which vary in number according to the area of the body and vary in size according to the nutritional state. Soft Tissue Abscess):
    • Superficial fatty layer (Camper’s fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis
    • Deeper membranous layer (Scarpa’s fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis)
  • Anterior fascial layer:
    • Anterior rectus sheath (medial)
    • External abdominal oblique fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis (lateral)
  • Abdominal muscles:
    • Rectus abdominis Rectus Abdominis A long flat muscle that extends along the whole length of both sides of the abdomen. It flexes the vertebral column, particularly the lumbar portion; it also tenses the anterior abdominal wall and assists in compressing the abdominal contents. It is frequently the site of hematomas. In reconstructive surgery it is often used for the creation of myocutaneous flaps. Anterior Abdominal Wall: Anatomy
    • External abdominal oblique
    • Internal abdominal oblique
    • Transversus abdominis Transversus abdominis Anterior Abdominal Wall: Anatomy
  • Posterior fascial layer:
    • Posterior rectus sheath (medial; ends at the arcuate line midway between umbilicus and pubic symphysis Pubic Symphysis A slightly movable cartilaginous joint which occurs between the pubic bones. Vagina, Vulva, and Pelvic Floor: Anatomy)
    • Transversalis fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis (lateral)
  • Peritoneum Peritoneum The peritoneum is a serous membrane lining the abdominopelvic cavity. This lining is formed by connective tissue and originates from the mesoderm. The membrane lines both the abdominal walls (as parietal peritoneum) and all of the visceral organs (as visceral peritoneum). Peritoneum: Anatomy
Diagram of the layers of abdominal wall

Layers of abdominal wall

Image: “Gray399” by Henry Gray. License: Public Domain, edited by Lecturio.

Relevant procedure

Ventral herniorrhaphy: surgical repair of hernias of abdominal wall

Right Hypochondrium

The surgically relevant structures of the right hypochondrium Hypochondrium Anterior Abdominal Wall: Anatomy include the liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy and the biliary tree Biliary tree The bile ducts and the gallbladder. Gallbladder and Biliary Tract: Anatomy.

Liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy

Location: 

  • ¾ in the RUQ
  • Adjacent to the inferior surface of diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy
  • Location is breath-dependent (rises during exhalation, lowers during inhalation).
Location of the liver in the right hypochondrium and epigastrium

Location of the liver in the right hypochondrium and epigastrium

Image by Lecturio. License: CC BY-NC-SA 4.0

Limits:

  • Superior: 5th intercostal space during exhalation
  • Inferior: right costal arch during inhalation 

Surfaces: 

  • Diaphragmatic and visceral
  • Liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy is intraperitoneal Intraperitoneal Peritoneum: Anatomy except for bare area, porta hepatis Porta hepatis Liver: Anatomy, and gallbladder Gallbladder The gallbladder is a pear-shaped sac, located directly beneath the liver, that sits on top of the superior part of the duodenum. The primary functions of the gallbladder include concentrating and storing up to 50 mL of bile. Gallbladder and Biliary Tract: Anatomy fossa.
  • Enclosed in the Glisson capsule Capsule An envelope of loose gel surrounding a bacterial cell which is associated with the virulence of pathogenic bacteria. Some capsules have a well-defined border, whereas others form a slime layer that trails off into the medium. Most capsules consist of relatively simple polysaccharides but there are some bacteria whose capsules are made of polypeptides. Bacteroides (external layer of fibrous Fibrous Fibrocystic Change connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue: Histology)

Biliary tree Biliary tree The bile ducts and the gallbladder. Gallbladder and Biliary Tract: Anatomy

Gallbladder Gallbladder The gallbladder is a pear-shaped sac, located directly beneath the liver, that sits on top of the superior part of the duodenum. The primary functions of the gallbladder include concentrating and storing up to 50 mL of bile. Gallbladder and Biliary Tract: Anatomy:

  • Bile-filled sac located in a fossa on the inferior aspect of the liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy beneath the junction of hepatic segments Ⅳb and Ⅴ
  • 7–10 cm in length, average capacity 30–50 mL
  • Anatomic divisions:
    • Fundus Fundus The superior portion of the body of the stomach above the level of the cardiac notch. Stomach: Anatomy (superiormost aspect)
    • Corpus (body)
    • Infundibulum Infundibulum Uterus, Cervix, and Fallopian Tubes: Anatomy (round, blind end extending below the liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy margin)
    • Neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess (connects with cystic Cystic Fibrocystic Change duct)
  • The cystic Cystic Fibrocystic Change duct connects the gallbladder Gallbladder The gallbladder is a pear-shaped sac, located directly beneath the liver, that sits on top of the superior part of the duodenum. The primary functions of the gallbladder include concentrating and storing up to 50 mL of bile. Gallbladder and Biliary Tract: Anatomy to the biliary tree Biliary tree The bile ducts and the gallbladder. Gallbladder and Biliary Tract: Anatomy.

Biliary tree Biliary tree The bile ducts and the gallbladder. Gallbladder and Biliary Tract: Anatomy:

  • The right and left hepatic ducts join to form the common hepatic duct.
  • The cystic Cystic Fibrocystic Change duct joins the common hepatic duct to form the common bile Bile An emulsifying agent produced in the liver and secreted into the duodenum. Its composition includes bile acids and salts; cholesterol; and electrolytes. It aids digestion of fats in the duodenum. Gallbladder and Biliary Tract: Anatomy duct.
  • The cystic Cystic Fibrocystic Change duct length is highly variable Variable Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups. Types of Variables.
Anatomy of the gallbladder and the biliary tree

Anatomy of the gallbladder and the biliary tree

Image by Lecturio. License: CC BY-NC-SA 4.0

Relevant procedures

  • Cholecystectomy Cholecystectomy Cholecystectomy is a surgical procedure performed with the goal of resecting and extracting the gallbladder. It is one of the most common abdominal surgeries performed in the Western world. Cholecystectomy is performed for symptomatic cholelithiasis, cholecystitis, gallbladder polyps > 0.5 cm, porcelain gallbladder, choledocholithiasis and gallstone pancreatitis, and rarely, for gallbladder cancer. Cholecystectomy (open and laparoscopic): surgical removal of the gallbladder Gallbladder The gallbladder is a pear-shaped sac, located directly beneath the liver, that sits on top of the superior part of the duodenum. The primary functions of the gallbladder include concentrating and storing up to 50 mL of bile. Gallbladder and Biliary Tract: Anatomy, usually because of cholelithiasis Cholelithiasis Cholelithiasis (gallstones) is the presence of stones in the gallbladder. Most gallstones are cholesterol stones, while the rest are composed of bilirubin (pigment stones) and other mixed components. Patients are commonly asymptomatic but may present with biliary colic (intermittent pain in the right upper quadrant). Cholelithiasis (gallstone disease) with or without cholecystitis Cholecystitis Cholecystitis is the inflammation of the gallbladder (GB) usually caused by the obstruction of the cystic duct (acute cholecystitis). Mechanical irritation by gallstones can also produce chronic GB inflammation. Cholecystitis is one of the most common complications of cholelithiasis but inflammation without gallstones can occur in a minority of patients. Cholecystitis
  • Choledochostomy: surgical incision Surgical Incision Surgical Site Infections on the common bile Bile An emulsifying agent produced in the liver and secreted into the duodenum. Its composition includes bile acids and salts; cholesterol; and electrolytes. It aids digestion of fats in the duodenum. Gallbladder and Biliary Tract: Anatomy duct
  • Choledochojejunostomy: anastomosis of a common bile Bile An emulsifying agent produced in the liver and secreted into the duodenum. Its composition includes bile acids and salts; cholesterol; and electrolytes. It aids digestion of fats in the duodenum. Gallbladder and Biliary Tract: Anatomy duct to the jejunum Jejunum The middle portion of the small intestine, between duodenum and ileum. It represents about 2/5 of the remaining portion of the small intestine below duodenum. Small Intestine: Anatomy (for oncologic resections or treatment of common bile Bile An emulsifying agent produced in the liver and secreted into the duodenum. Its composition includes bile acids and salts; cholesterol; and electrolytes. It aids digestion of fats in the duodenum. Gallbladder and Biliary Tract: Anatomy duct injuries)
  • Hepatic lobectomy: surgical removal of a lobe of the liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy
  • Hepatic segmentectomy: surgical removal of a segment of the liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy
  • Needle biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma of the liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy
  • Hepatic abscess Abscess Accumulation of purulent material in tissues, organs, or circumscribed spaces, usually associated with signs of infection. Chronic Granulomatous Disease drainage
Laparoscopic cholecystectomy

Incisions for open (left) and laparoscopic (right) cholecystectomy

Image by Lecturio. License: CC BY-NC-SA 4.0

Epigastrium

The epigastrium contains the transverse colon Transverse colon The segment of large intestine between ascending colon and descending colon. It passes from the right colic flexure across the abdomen, then turns sharply at the left colonic flexure into the descending colon. Colon, Cecum, and Appendix: Anatomy, the duodenum Duodenum The shortest and widest portion of the small intestine adjacent to the pylorus of the stomach. It is named for having the length equal to about the width of 12 fingers. Small Intestine: Anatomy, and the pancreas Pancreas The pancreas lies mostly posterior to the stomach and extends across the posterior abdominal wall from the duodenum on the right to the spleen on the left. This organ has both exocrine and endocrine tissue. Pancreas: Anatomy.

Transverse colon Transverse colon The segment of large intestine between ascending colon and descending colon. It passes from the right colic flexure across the abdomen, then turns sharply at the left colonic flexure into the descending colon. Colon, Cecum, and Appendix: Anatomy

  • Part of the colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy distal to the ascending colon Ascending colon The segment of large intestine between the cecum and the transverse colon. It passes cephalad from the cecum to the caudal surface of the right lobe of the liver where it bends sharply to the left, forming the right colic flexure. Colon, Cecum, and Appendix: Anatomy and proximal to the descending colon Descending colon The segment of large intestine between transverse colon and the sigmoid colon. Colon, Cecum, and Appendix: Anatomy that travels transversely across the upper abdomen
  • Suspended by mesentery Mesentery A layer of the peritoneum which attaches the abdominal viscera to the abdominal wall and conveys their blood vessels and nerves. Peritoneum: Anatomy (transverse mesocolon)
  • Supplied by ileocolic and middle colic branches of the superior mesenteric artery Superior mesenteric artery A large vessel supplying the whole length of the small intestine except the superior part of the duodenum. It also supplies the cecum and the ascending part of the colon and about half the transverse part of the colon. It arises from the anterior surface of the aorta below the celiac artery at the level of the first lumbar vertebra. Small Intestine: Anatomy
  • Venous drainage is through the superior mesenteric vein that joins the portal vein Portal vein A short thick vein formed by union of the superior mesenteric vein and the splenic vein. Liver: Anatomy.
Colon in situ covered by the greater omentum

Colon in situ, covered by the greater omentum

Image by BioDigital, edited by Lecturio

Duodenum Duodenum The shortest and widest portion of the small intestine adjacent to the pylorus of the stomach. It is named for having the length equal to about the width of 12 fingers. Small Intestine: Anatomy

  • First C-shaped segment of the small intestine Small intestine The small intestine is the longest part of the GI tract, extending from the pyloric orifice of the stomach to the ileocecal junction. The small intestine is the major organ responsible for chemical digestion and absorption of nutrients. It is divided into 3 segments: the duodenum, the jejunum, and the ileum. Small Intestine: Anatomy
  • Surrounds the head of the pancreas Pancreas The pancreas lies mostly posterior to the stomach and extends across the posterior abdominal wall from the duodenum on the right to the spleen on the left. This organ has both exocrine and endocrine tissue. Pancreas: Anatomy
  • Consists of 4 segments
  • The 2nd, or descending, segment contains the ampulla of Vater (opening of the common bile Bile An emulsifying agent produced in the liver and secreted into the duodenum. Its composition includes bile acids and salts; cholesterol; and electrolytes. It aids digestion of fats in the duodenum. Gallbladder and Biliary Tract: Anatomy duct).
  • 1st segment (duodenal bulb): intraperitoneal Intraperitoneal Peritoneum: Anatomy
  • Descending, horizontal, and ascending parts: retroperitoneal Retroperitoneal Peritoneum: Anatomy
  • Ends at duodenojejunal flexure: fixed to the posterior abdominal wall Posterior abdominal wall The posterior abdominal wall is a complex musculoskeletal structure that houses the abdominal aorta, the inferior vena cava, as well as important retroperitoneal organs, like the kidneys, renal glands, pancreas, and duodenum. Posterior Abdominal Wall: Anatomy by the ligament of Treitz Ligament of treitz Gastrointestinal Bleeding
Anatomy of the gallbladder and the biliary tree (cholecystectomy)

Duodenum and its relation with the pancreas and biliary ducts

Image by Lecturio. License: CC BY-NC-SA 4.0

Pancreas Pancreas The pancreas lies mostly posterior to the stomach and extends across the posterior abdominal wall from the duodenum on the right to the spleen on the left. This organ has both exocrine and endocrine tissue. Pancreas: Anatomy

Segments:

  • Caput pancreatis (head)
  • Uncinate process
  • Collum pancreatis ( neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess)
  • Corpus pancreatis (body)
  • Cauda pancreatis (tail): the only intraperitoneal Intraperitoneal Peritoneum: Anatomy segment of the pancreas Pancreas The pancreas lies mostly posterior to the stomach and extends across the posterior abdominal wall from the duodenum on the right to the spleen on the left. This organ has both exocrine and endocrine tissue. Pancreas: Anatomy 

Ducts:

  • Pancreatic duct (Wirsung’s duct) and common bile Bile An emulsifying agent produced in the liver and secreted into the duodenum. Its composition includes bile acids and salts; cholesterol; and electrolytes. It aids digestion of fats in the duodenum. Gallbladder and Biliary Tract: Anatomy duct open into ampulla of Vater, which presents as major duodenal papilla.
  • Major duodenal papilla contains the hepatopancreatic sphincter (sphincter of Oddi), which regulates the secretion Secretion Coagulation Studies of bile Bile An emulsifying agent produced in the liver and secreted into the duodenum. Its composition includes bile acids and salts; cholesterol; and electrolytes. It aids digestion of fats in the duodenum. Gallbladder and Biliary Tract: Anatomy and pancreatic fluid.
  • Accessory pancreatic duct Accessory pancreatic duct Pancreas: Anatomy (when present) opens into minor duodenal papilla.
The pancreas

Different parts of the pancreas and its surroundings

Image: “The pancreas” by OpenStax College. License: CC BY 3.0

Relevant procedures

  • Transverse colostomy: an opening along the length of the transverse colon Transverse colon The segment of large intestine between ascending colon and descending colon. It passes from the right colic flexure across the abdomen, then turns sharply at the left colonic flexure into the descending colon. Colon, Cecum, and Appendix: Anatomy to the exterior skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions surface
  • Transverse hemicolectomy: surgical removal of the transverse colon Transverse colon The segment of large intestine between ascending colon and descending colon. It passes from the right colic flexure across the abdomen, then turns sharply at the left colonic flexure into the descending colon. Colon, Cecum, and Appendix: Anatomy
  • Pancreaticojejunostomy (Puestow procedure): surgically made communication Communication The exchange or transmission of ideas, attitudes, or beliefs between individuals or groups. Decision-making Capacity and Legal Competence between the pancreas Pancreas The pancreas lies mostly posterior to the stomach and extends across the posterior abdominal wall from the duodenum on the right to the spleen on the left. This organ has both exocrine and endocrine tissue. Pancreas: Anatomy and the jejunum Jejunum The middle portion of the small intestine, between duodenum and ileum. It represents about 2/5 of the remaining portion of the small intestine below duodenum. Small Intestine: Anatomy (treatment of chronic pancreatitis Pancreatitis Inflammation of the pancreas. Pancreatitis is classified as acute unless there are computed tomographic or endoscopic retrograde cholangiopancreatographic findings of chronic pancreatitis. The two most common forms of acute pancreatitis are alcoholic pancreatitis and gallstone pancreatitis. Acute Pancreatitis)
  • Pancreaticoduodenectomy (Whipple procedure): surgical removal of the head of the pancreas Pancreas The pancreas lies mostly posterior to the stomach and extends across the posterior abdominal wall from the duodenum on the right to the spleen on the left. This organ has both exocrine and endocrine tissue. Pancreas: Anatomy and the duodenum Duodenum The shortest and widest portion of the small intestine adjacent to the pylorus of the stomach. It is named for having the length equal to about the width of 12 fingers. Small Intestine: Anatomy
  • Distal pancreatectomy: removal of the body and tail of the pancreas Pancreas The pancreas lies mostly posterior to the stomach and extends across the posterior abdominal wall from the duodenum on the right to the spleen on the left. This organ has both exocrine and endocrine tissue. Pancreas: Anatomy
  • Total pancreatectomy: surgical removal of the pancreas Pancreas The pancreas lies mostly posterior to the stomach and extends across the posterior abdominal wall from the duodenum on the right to the spleen on the left. This organ has both exocrine and endocrine tissue. Pancreas: Anatomy

Left Hypochondrium

The most important structures of the left hypochondrium Hypochondrium Anterior Abdominal Wall: Anatomy are the spleen Spleen The spleen is the largest lymphoid organ in the body, located in the LUQ of the abdomen, superior to the left kidney and posterior to the stomach at the level of the 9th-11th ribs just below the diaphragm. The spleen is highly vascular and acts as an important blood filter, cleansing the blood of pathogens and damaged erythrocytes. Spleen: Anatomy and the stomach Stomach The stomach is a muscular sac in the upper left portion of the abdomen that plays a critical role in digestion. The stomach develops from the foregut and connects the esophagus with the duodenum. Structurally, the stomach is C-shaped and forms a greater and lesser curvature and is divided grossly into regions: the cardia, fundus, body, and pylorus. Stomach: Anatomy.

Spleen Spleen The spleen is the largest lymphoid organ in the body, located in the LUQ of the abdomen, superior to the left kidney and posterior to the stomach at the level of the 9th-11th ribs just below the diaphragm. The spleen is highly vascular and acts as an important blood filter, cleansing the blood of pathogens and damaged erythrocytes. Spleen: Anatomy

Location:

  • Positioned against ribs Ribs A set of twelve curved bones which connect to the vertebral column posteriorly, and terminate anteriorly as costal cartilage. Together, they form a protective cage around the internal thoracic organs. Chest Wall: Anatomy 9–11
  • Intraperitoneal Intraperitoneal Peritoneum: Anatomy

Relations:

  • Anterior: stomach Stomach The stomach is a muscular sac in the upper left portion of the abdomen that plays a critical role in digestion. The stomach develops from the foregut and connects the esophagus with the duodenum. Structurally, the stomach is C-shaped and forms a greater and lesser curvature and is divided grossly into regions: the cardia, fundus, body, and pylorus. Stomach: Anatomy
  • Lateral: abdominal muscles
  • Medial: left kidney
  • Posterior: diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy
  • Inferior: colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy and left colic flexure

Ligaments:

  • Gastrosplenic
  • Splenorenal
  • Phrenicocolic

Blood supply: splenic artery and vein

Stomach Stomach The stomach is a muscular sac in the upper left portion of the abdomen that plays a critical role in digestion. The stomach develops from the foregut and connects the esophagus with the duodenum. Structurally, the stomach is C-shaped and forms a greater and lesser curvature and is divided grossly into regions: the cardia, fundus, body, and pylorus. Stomach: Anatomy

Segments:

  • Has 2 curvatures (lesser and greater) 
  • Cardia:
    • Entrance of the stomach Stomach The stomach is a muscular sac in the upper left portion of the abdomen that plays a critical role in digestion. The stomach develops from the foregut and connects the esophagus with the duodenum. Structurally, the stomach is C-shaped and forms a greater and lesser curvature and is divided grossly into regions: the cardia, fundus, body, and pylorus. Stomach: Anatomy
    • Originates from the z-line Z-line Esophagus: Anatomy and creates the angle of His, or angle of the cardiac orifice (the angle between the fundus Fundus The superior portion of the body of the stomach above the level of the cardiac notch. Stomach: Anatomy and abdominal esophagus Esophagus The esophagus is a muscular tube-shaped organ of around 25 centimeters in length that connects the pharynx to the stomach. The organ extends from approximately the 6th cervical vertebra to the 11th thoracic vertebra and can be divided grossly into 3 parts: the cervical part, the thoracic part, and the abdominal part. Esophagus: Anatomy)
    • Crucial landmark in the construction of the gastric pouch 
  • Fundus Fundus The superior portion of the body of the stomach above the level of the cardiac notch. Stomach: Anatomy: a dome-shaped region located at the highest point of the stomach Stomach The stomach is a muscular sac in the upper left portion of the abdomen that plays a critical role in digestion. The stomach develops from the foregut and connects the esophagus with the duodenum. Structurally, the stomach is C-shaped and forms a greater and lesser curvature and is divided grossly into regions: the cardia, fundus, body, and pylorus. Stomach: Anatomy
  • Body: 
    • Main section of the stomach Stomach The stomach is a muscular sac in the upper left portion of the abdomen that plays a critical role in digestion. The stomach develops from the foregut and connects the esophagus with the duodenum. Structurally, the stomach is C-shaped and forms a greater and lesser curvature and is divided grossly into regions: the cardia, fundus, body, and pylorus. Stomach: Anatomy
    • Extends from the fundus Fundus The superior portion of the body of the stomach above the level of the cardiac notch. Stomach: Anatomy to the pylorus Pylorus The region between the sharp indentation at the lower third of the stomach (incisura angularis) and the junction of the pylorus with the duodenum. Pyloric antral glands contain mucus-secreting cells and gastrin-secreting endocrine cells (g cells). Stomach: Anatomy
    • Bordered by the lesser and greater curvatures
  • Pylorus Pylorus The region between the sharp indentation at the lower third of the stomach (incisura angularis) and the junction of the pylorus with the duodenum. Pyloric antral glands contain mucus-secreting cells and gastrin-secreting endocrine cells (g cells). Stomach: Anatomy
    • Connects to the duodenum Duodenum The shortest and widest portion of the small intestine adjacent to the pylorus of the stomach. It is named for having the length equal to about the width of 12 fingers. Small Intestine: Anatomy
    • Contains the pyloric sphincter
    • Consists of a wide pyloric antrum and narrow pyloric canal

Arterial supply:

  • Left gastric artery Gastric artery Any of several branches of the splenic artery distributed to the greater curvature of the stomach. Stomach: Anatomy: main supply of the gastric pouch in a gastric bypass Gastric bypass Surgical procedure in which the stomach is transected high on the body. The resulting small proximal gastric pouch is joined to any parts of the small intestine by an end-to-side surgical anastomosis, depending on the amounts of intestinal surface being bypasses. This procedure is used frequently in the treatment of morbid obesity by limiting the size of functional stomach, food intake, and food absorption. Gastroesophageal Reflux Disease (GERD)
  • Right gastric artery Gastric artery Any of several branches of the splenic artery distributed to the greater curvature of the stomach. Stomach: Anatomy
  • Right and left gastroepiploic (gastro-omental) arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology
  • Splenic artery
  • Short gastric arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology
  • Posterior gastric artery Gastric artery Any of several branches of the splenic artery distributed to the greater curvature of the stomach. Stomach: Anatomy

Venous drainage:

  • Homonymous veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology that accompany the arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology
  • Right and left gastric veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology drain into the portal vein Portal vein A short thick vein formed by union of the superior mesenteric vein and the splenic vein. Liver: Anatomy.
  • Left gastroepiploic vein drains into the splenic vein.
  • Right gastroepiploic vein drains into the superior mesenteric vein.

Innervation:

  • Parasympathetic innervation: anterior and posterior vagal trunk
  • Sympathetic innervation: greater splanchnic nerve and gastric branches from celiac plexus
Blood supply and innervation of the stomach

Blood supply and innervation of the stomach

Image by BioDigital, edited by Lecturio

Relevant procedures

  • Splenectomy Splenectomy Surgical procedure involving either partial or entire removal of the spleen. Rupture of the Spleen: surgical removal of the spleen Spleen The spleen is the largest lymphoid organ in the body, located in the LUQ of the abdomen, superior to the left kidney and posterior to the stomach at the level of the 9th-11th ribs just below the diaphragm. The spleen is highly vascular and acts as an important blood filter, cleansing the blood of pathogens and damaged erythrocytes. Spleen: Anatomy
  • Splenorrhaphy: surgical repair of the spleen Spleen The spleen is the largest lymphoid organ in the body, located in the LUQ of the abdomen, superior to the left kidney and posterior to the stomach at the level of the 9th-11th ribs just below the diaphragm. The spleen is highly vascular and acts as an important blood filter, cleansing the blood of pathogens and damaged erythrocytes. Spleen: Anatomy, usually performed after trauma
  • Bariatric surgery Bariatric surgery Bariatric surgery refers to a group of invasive procedures used to surgically reduce the size of the stomach to produce early satiety, decrease food intake (restrictive type) and/or alter digestion, and artificially induce malabsorption of nutrients (malabsorptive type). The ultimate goal of bariatric surgery is drastic weight loss. Bariatric Surgery: group of invasive procedures that surgically reduce the size of the stomach Stomach The stomach is a muscular sac in the upper left portion of the abdomen that plays a critical role in digestion. The stomach develops from the foregut and connects the esophagus with the duodenum. Structurally, the stomach is C-shaped and forms a greater and lesser curvature and is divided grossly into regions: the cardia, fundus, body, and pylorus. Stomach: Anatomy to produce early satiety Early Satiety Bariatric Surgery and decrease food intake (restrictive type) and/or alter digestion Digestion Digestion refers to the process of the mechanical and chemical breakdown of food into smaller particles, which can then be absorbed and utilized by the body. Digestion and Absorption and artificially induce malabsorption Malabsorption General term for a group of malnutrition syndromes caused by failure of normal intestinal absorption of nutrients. Malabsorption and Maldigestion of nutrients (malabsorptive type).
  • Total and subtotal gastrectomy: surgical removal of a part of or an entire stomach Stomach The stomach is a muscular sac in the upper left portion of the abdomen that plays a critical role in digestion. The stomach develops from the foregut and connects the esophagus with the duodenum. Structurally, the stomach is C-shaped and forms a greater and lesser curvature and is divided grossly into regions: the cardia, fundus, body, and pylorus. Stomach: Anatomy (for oncologic resections and gastric ulcers)
  • Truncal or selective vagotomy: transection of the vagal nerves or branches that can be combined with partial gastric resections to control acid secretion Secretion Coagulation Studies and prevent ulcer recurrence

Right and Left Flanks

Ascending and descending colon Descending colon The segment of large intestine between transverse colon and the sigmoid colon. Colon, Cecum, and Appendix: Anatomy

  • Ascending and descending portions of the large intestine Large intestine The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy found in the right flank and the left flank, respectively
  • Arterial supply: superior and inferior mesenteric arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology
  • Venous drainage: superior and inferior mesenteric veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology that join portal circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment
Colon blood supply, anterior view

Colon in situ, anterior view, with the greater omentum and small intestines removed

Image by BioDigital, edited by Lecturio

Kidneys Kidneys The kidneys are a pair of bean-shaped organs located retroperitoneally against the posterior wall of the abdomen on either side of the spine. As part of the urinary tract, the kidneys are responsible for blood filtration and excretion of water-soluble waste in the urine. Kidneys: Anatomy

Location:

  • Between T12 and L3, in the paravertebral gutter
  • Their superior pole rests at the level of the 11th and 12th ribs Ribs A set of twelve curved bones which connect to the vertebral column posteriorly, and terminate anteriorly as costal cartilage. Together, they form a protective cage around the internal thoracic organs. Chest Wall: Anatomy.
  • The parietal Parietal One of a pair of irregularly shaped quadrilateral bones situated between the frontal bone and occipital bone, which together form the sides of the cranium. Skull: Anatomy peritoneum Peritoneum The peritoneum is a serous membrane lining the abdominopelvic cavity. This lining is formed by connective tissue and originates from the mesoderm. The membrane lines both the abdominal walls (as parietal peritoneum) and all of the visceral organs (as visceral peritoneum). Peritoneum: Anatomy anchors them to the posterior abdominal wall Posterior abdominal wall The posterior abdominal wall is a complex musculoskeletal structure that houses the abdominal aorta, the inferior vena cava, as well as important retroperitoneal organs, like the kidneys, renal glands, pancreas, and duodenum. Posterior Abdominal Wall: Anatomy
  • Retroperitoneal Retroperitoneal Peritoneum: Anatomy

Renal capsule Renal capsule Pyelonephritis and Perinephric Abscess:

  • Holds the kidneys Kidneys The kidneys are a pair of bean-shaped organs located retroperitoneally against the posterior wall of the abdomen on either side of the spine. As part of the urinary tract, the kidneys are responsible for blood filtration and excretion of water-soluble waste in the urine. Kidneys: Anatomy in position
  • Consists of:
    • Paranephric adipose tissue Adipose tissue Adipose tissue is a specialized type of connective tissue that has both structural and highly complex metabolic functions, including energy storage, glucose homeostasis, and a multitude of endocrine capabilities. There are three types of adipose tissue, white adipose tissue, brown adipose tissue, and beige or “brite” adipose tissue, which is a transitional form. Adipose Tissue: Histology (fat)
    • Renal fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis

Relations:

  • Superomedially: adrenal glands Adrenal Glands The adrenal glands are a pair of retroperitoneal endocrine glands located above the kidneys. The outer parenchyma is called the adrenal cortex and has 3 distinct zones, each with its own secretory products. Beneath the cortex lies the adrenal medulla, which secretes catecholamines involved in the fight-or-flight response. Adrenal Glands: Anatomy
  • Posteriorly:
    • Nerves: subcostal, iliohypogastric, ilioinguinal
    • Muscles: diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy, quadratus lumborum Quadratus lumborum Posterior Abdominal Wall: Anatomy

External characteristics:

  • Superior pole
  • Inferior pole
  • Convex lateral surface
  • Concave medial surface: renal hilum Hilum Lungs: Anatomy

Blood supply: renal arteries and veins Arteries And Veins ACES and RUSH: Resuscitation Ultrasound Protocols

Transverse cross section of the abdomen focused on the kidneys

Transverse cross section of the abdomen focused on the kidneys:
Note how the kidney is embedded in adipose tissue within the gutters (paranephric and perinephric fat), which is continuous with the fat in the renal sinuses.

Image by Lecturio. License: CC BY-NC-SA 4.0

Relevant procedures

Umbilical Region

Small intestine Small intestine The small intestine is the longest part of the GI tract, extending from the pyloric orifice of the stomach to the ileocecal junction. The small intestine is the major organ responsible for chemical digestion and absorption of nutrients. It is divided into 3 segments: the duodenum, the jejunum, and the ileum. Small Intestine: Anatomy

  • Average length: 6–7 m
  • Segments:
    • Duodenum Duodenum The shortest and widest portion of the small intestine adjacent to the pylorus of the stomach. It is named for having the length equal to about the width of 12 fingers. Small Intestine: Anatomy
    • Jejunum Jejunum The middle portion of the small intestine, between duodenum and ileum. It represents about 2/5 of the remaining portion of the small intestine below duodenum. Small Intestine: Anatomy
    • Ileum Ileum The distal and narrowest portion of the small intestine, between the jejunum and the ileocecal valve of the large intestine. Small Intestine: Anatomy

Blood supply: 

  • Duodenum Duodenum The shortest and widest portion of the small intestine adjacent to the pylorus of the stomach. It is named for having the length equal to about the width of 12 fingers. Small Intestine: Anatomy: superior and inferior pancreaticoduodenal arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology
  • Jejunum Jejunum The middle portion of the small intestine, between duodenum and ileum. It represents about 2/5 of the remaining portion of the small intestine below duodenum. Small Intestine: Anatomy and ilium: jejunal arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology and ileal arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology
    • Form anastomotic loops that run parallel to the small intestine Small intestine The small intestine is the longest part of the GI tract, extending from the pyloric orifice of the stomach to the ileocecal junction. The small intestine is the major organ responsible for chemical digestion and absorption of nutrients. It is divided into 3 segments: the duodenum, the jejunum, and the ileum. Small Intestine: Anatomy = arcades
    • Small branches leave these arcades = vasa recta Vasa recta Glomerular Filtration (or straight arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology)
  • Venous drainage: portal system
Small intestine and its parts

Small intestine and its parts

Image: “2417 Small IntestineN” by OpenStax College. License: CC BY 3.0

Abdominal aorta Abdominal Aorta The aorta from the diaphragm to the bifurcation into the right and left common iliac arteries. Posterior Abdominal Wall: Anatomy

  • Retroperitoneal Retroperitoneal Peritoneum: Anatomy
  • Extending from the aortic hiatus Aortic hiatus Diaphragm: Anatomy of the diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy (T12) to its bifurcation into the common iliac arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology (L4)

Vascular branches: 

  • Unpaired (forward branches):
    • Celiac trunk
    • Superior mesenteric 
    • Inferior mesenteric 
  • Paired visceral (lateral):
    • Renal
    • Gonadal
  • Paired parietal Parietal One of a pair of irregularly shaped quadrilateral bones situated between the frontal bone and occipital bone, which together form the sides of the cranium. Skull: Anatomy (posterolateral): inferiormost intercostal

Relevant procedures

  • Small intestine Small intestine The small intestine is the longest part of the GI tract, extending from the pyloric orifice of the stomach to the ileocecal junction. The small intestine is the major organ responsible for chemical digestion and absorption of nutrients. It is divided into 3 segments: the duodenum, the jejunum, and the ileum. Small Intestine: Anatomy resection: surgical removal of a segment of the small intestine Small intestine The small intestine is the longest part of the GI tract, extending from the pyloric orifice of the stomach to the ileocecal junction. The small intestine is the major organ responsible for chemical digestion and absorption of nutrients. It is divided into 3 segments: the duodenum, the jejunum, and the ileum. Small Intestine: Anatomy, usually because of adhesions, volvulus Volvulus A volvulus is the twisting or axial rotation of a portion of the bowel around its mesentery. The most common site of volvulus in adults is the colon; most frequently the sigmoid volvulus. Patients typically present with symptoms of bowel obstruction such as abdominal pain, distension, vomiting, and constipation/obstipation. Volvulus, obstruction, and regional ileitis
  • Ileostomy Ileostomy Surgical creation of an external opening into the ileum for fecal diversion or drainage. This replacement for the rectum is usually created in patients with severe inflammatory bowel diseases. Loop (continent) or tube (incontinent) procedures are most often employed. Large Bowel Obstruction: surgically made communication Communication The exchange or transmission of ideas, attitudes, or beliefs between individuals or groups. Decision-making Capacity and Legal Competence between the ileum Ileum The distal and narrowest portion of the small intestine, between the jejunum and the ileocecal valve of the large intestine. Small Intestine: Anatomy and the skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions 
  • Aortic aneurysm Aortic aneurysm An abnormal balloon- or sac-like dilatation in the wall of aorta. Thoracic Aortic Aneurysms repair using grafts

Right and Left Inguinal Regions (Iliac Fossae)

Appendix Appendix A worm-like blind tube extension from the cecum. Colon, Cecum, and Appendix: Anatomy

McBurney’s point McBurney’s point Appendicitis:

  • Junction between the lateral and medial thirds of a line drawn from the anterior superior iliac spine Anterior Superior Iliac Spine Chronic Apophyseal Injury ( ASIS ASIS Chronic Apophyseal Injury) to the umbilicus
  • Localized tenderness at this point is a classic sign of appendicitis Appendicitis Appendicitis is the acute inflammation of the vermiform appendix and the most common abdominal surgical emergency globally. The condition has a lifetime risk of 8%. Characteristic features include periumbilical abdominal pain that migrates to the right lower quadrant, fever, anorexia, nausea, and vomiting. Appendicitis.
  • Both McBurney’s and Rocky-Davis incisions for open appendectomy Open Appendectomy Appendectomy are performed through this point.

Inguinal canals

Boundaries:

  • Superior: inferior edge of the internal oblique Internal oblique Muscles of the anterolateral abdominal wall consisting of the external oblique and the internal oblique muscles. The external abdominal oblique muscle fibers extend from lower thoracic ribs to the linea alba and the iliac crest. The internal abdominal oblique extend superomedially beneath the external oblique muscles. Anterior Abdominal Wall: Anatomy and transverse abdominal muscles
  • Inferior: inguinal ligament Inguinal Ligament Femoral Region and Hernias: Anatomy (continuation of the external abdominal oblique aponeurosis)
  • Anterior: aponeurosis of the abdominal external oblique External oblique Muscles of the anterolateral abdominal wall consisting of the external oblique and the internal oblique muscles. The external abdominal oblique muscle fibers extend from lower thoracic ribs to the linea alba and the iliac crest. The internal abdominal oblique extend superomedially beneath the external oblique muscles. Anterior Abdominal Wall: Anatomy muscle
  • Posterior: transversalis fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis and interfoveolar ligament

Course:

The layers of the anterior abdominal wall

The layers of the anterior abdominal wall, depicting the course of the inguinal canal and the composition of the deep and superficial inguinal rings

Image by Lecturio. License: CC BY-NC-SA 4.0

Contents:

Boundaries and contents of the male inguinal canal

Boundaries and contents of the male inguinal canal
Note that the ilioinguinal nerve runs along the inguinal canal externally from the spermatic cord.

Image by Lecturio. License: CC BY-NC-SA 4.0

Descending and sigmoid Sigmoid A segment of the colon between the rectum and the descending colon. Volvulus colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy

  • Suspended by mesentery Mesentery A layer of the peritoneum which attaches the abdominal viscera to the abdominal wall and conveys their blood vessels and nerves. Peritoneum: Anatomy ( sigmoid Sigmoid A segment of the colon between the rectum and the descending colon. Volvulus mesocolon)
  • Arterial supply: inferior mesenteric artery Inferior mesenteric artery The artery supplying nearly all the left half of the transverse colon, the whole of the descending colon, the sigmoid colon, and the greater part of the rectum. It is smaller than the superior mesenteric artery and arises from the aorta above its bifurcation into the common iliac arteries. Small Intestine: Anatomy ( sigmoid Sigmoid A segment of the colon between the rectum and the descending colon. Volvulus arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology)
  • Venous drainage: inferior mesenteric vein → portal vein Portal vein A short thick vein formed by union of the superior mesenteric vein and the splenic vein. Liver: Anatomy

Fallopian tubes Fallopian tubes The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The fallopian tubes receive an ovum after ovulation and help move it and/or a fertilized embryo toward the uterus via ciliated cells lining the tubes and peristaltic movements of its smooth muscle. Uterus, Cervix, and Fallopian Tubes: Anatomy

Segments:

Broad ligament Broad Ligament A broad fold of peritoneum that extends from the side of the uterus to the wall of the pelvis. Uterus, Cervix, and Fallopian Tubes: Anatomy (ligamentum latum):

Blood supply:

  • Arterial: ovarian and uterine arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology
  • Venous supply is from ovarian veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology:

Relevant procedures

  • Appendectomy Appendectomy Appendectomy is an invasive surgical procedure performed with the goal of resecting and extracting the vermiform appendix through either an open or a laparoscopic approach. The most common indication is acute appendicitis. Appendectomy: surgical removal of the vermiform appendix Appendix A worm-like blind tube extension from the cecum. Colon, Cecum, and Appendix: Anatomy, most commonly because of appendicitis Appendicitis Appendicitis is the acute inflammation of the vermiform appendix and the most common abdominal surgical emergency globally. The condition has a lifetime risk of 8%. Characteristic features include periumbilical abdominal pain that migrates to the right lower quadrant, fever, anorexia, nausea, and vomiting. Appendicitis
  • Inguinal herniorrhaphy: surgical repair of inguinal hernias Inguinal Hernias An abdominal hernia with an external bulge in the groin region. It can be classified by the location of herniation. Indirect inguinal hernias occur through the internal inguinal ring. Direct inguinal hernias occur through defects in the abdominal wall (transversalis fascia) in Hesselbach’s triangle. The former type is commonly seen in children and young adults; the latter in adults. Inguinal Canal: Anatomy and Hernias; can be done laparoscopically or via an open approach (Lichtenstein technique is the most common)
  • Salpingectomy: surgical removal of the fallopian tube Fallopian Tube A pair of highly specialized canals extending from the uterus to its corresponding ovary. They provide the means for ovum transport from the ovaries and they are the site of the ovum’s final maturation and fertilization. The fallopian tube consists of an interstitium, an isthmus, an ampulla, an infundibulum, and fimbriae. Its wall consists of three layers: serous, muscular, and an internal mucosal layer lined with both ciliated and secretory cells. Uterus, Cervix, and Fallopian Tubes: Anatomy, commonly performed to treat ectopic pregnancy Ectopic pregnancy Ectopic pregnancy refers to the implantation of a fertilized egg (embryo) outside the uterine cavity. The main cause is disruption of the normal anatomy of the fallopian tube. Ectopic Pregnancy
  • Salpingostomy: incising the fallopian tube Fallopian Tube A pair of highly specialized canals extending from the uterus to its corresponding ovary. They provide the means for ovum transport from the ovaries and they are the site of the ovum’s final maturation and fertilization. The fallopian tube consists of an interstitium, an isthmus, an ampulla, an infundibulum, and fimbriae. Its wall consists of three layers: serous, muscular, and an internal mucosal layer lined with both ciliated and secretory cells. Uterus, Cervix, and Fallopian Tubes: Anatomy open, commonly to remove an occupying lesion ( ectopic pregnancy Ectopic pregnancy Ectopic pregnancy refers to the implantation of a fertilized egg (embryo) outside the uterine cavity. The main cause is disruption of the normal anatomy of the fallopian tube. Ectopic Pregnancy), leaving the remainder of the tube intact
  • Sigmoid Sigmoid A segment of the colon between the rectum and the descending colon. Volvulus colectomy: surgical removal of a sigmoid Sigmoid A segment of the colon between the rectum and the descending colon. Volvulus colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy, commonly performed for cancer or diverticulitis Diverticulitis Inflammation of a diverticulum or diverticula. Diverticular Disease
  • Rectosigmoidectomy: surgical removal of the sigmoid Sigmoid A segment of the colon between the rectum and the descending colon. Volvulus colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy and rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal: Anatomy
  • Descending colon Descending colon The segment of large intestine between transverse colon and the sigmoid colon. Colon, Cecum, and Appendix: Anatomy colostomy

Hypogastrium

Urinary bladder Urinary Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters (ureter), and is held there until urination. Urinary Tract: Anatomy

  • In females, the urinary bladder Urinary Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters (ureter), and is held there until urination. Urinary Tract: Anatomy is anterior to the uterus Uterus The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The uterus has a thick wall made of smooth muscle (the myometrium) and an inner mucosal layer (the endometrium). The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Uterus, Cervix, and Fallopian Tubes: Anatomy and anterior vaginal wall. 
  • In males, it is anterior to the rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal: Anatomy.
  • Anchored by median umbilical ligament

Prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid.

Location: 

Lobes:

  • Anterior lobe Anterior lobe Cerebellum: Anatomy ( isthmus Isthmus Uterus, Cervix, and Fallopian Tubes: Anatomy): located anterior to the urethra Urethra A tube that transports urine from the urinary bladder to the outside of the body in both the sexes. It also has a reproductive function in the male by providing a passage for sperm. Urinary Tract: Anatomy 
  • Posterior lobe Posterior lobe Cerebellum: Anatomy:
    • Posterior to urethra Urethra A tube that transports urine from the urinary bladder to the outside of the body in both the sexes. It also has a reproductive function in the male by providing a passage for sperm. Urinary Tract: Anatomy
    • Inferior to ejaculatory ducts Ejaculatory Ducts Paired ducts in the human male through which semen is ejaculated into the urethra.
  • Lateral lobes: located on either side of the urethra Urethra A tube that transports urine from the urinary bladder to the outside of the body in both the sexes. It also has a reproductive function in the male by providing a passage for sperm. Urinary Tract: Anatomy 
  • Median lobe: lies between the urethra Urethra A tube that transports urine from the urinary bladder to the outside of the body in both the sexes. It also has a reproductive function in the male by providing a passage for sperm. Urinary Tract: Anatomy and ejaculatory ducts Ejaculatory Ducts Paired ducts in the human male through which semen is ejaculated into the urethra.

Related structures:

  • The urethra Urethra A tube that transports urine from the urinary bladder to the outside of the body in both the sexes. It also has a reproductive function in the male by providing a passage for sperm. Urinary Tract: Anatomy enters the prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. near its anterior border and usually passes between its anterior and middle thirds.
  • The ejaculatory ducts Ejaculatory Ducts Paired ducts in the human male through which semen is ejaculated into the urethra. pass anteroinferiorly through its posterior region to open into the prostatic urethra Prostatic urethra .

Accessory glandular structures:

Prostate gland and main prostate zones

Prostate gland and main prostate zones:
Peripheral, transitional, and central zones in relation to other structures of the male genitourinary system
Note how the prostate is positioned around the prostatic urethra.

Image: “Prostate zones” by Mikael Häggström. License: CC0 1.0

Uterus Uterus The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The uterus has a thick wall made of smooth muscle (the myometrium) and an inner mucosal layer (the endometrium). The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Uterus, Cervix, and Fallopian Tubes: Anatomy

Location:

  • 7–9 cm long, found within the pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 “hip” bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy, connected to the end of the vaginal canal via the uterine cervix Cervix The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Externally, the cervix is lined by stratified squamous cells; however, the cervical canal is lined by columnar epithelium. Uterus, Cervix, and Fallopian Tubes: Anatomy 
  • Dorsal to the urinary bladder Urinary Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters (ureter), and is held there until urination. Urinary Tract: Anatomy, anterior to the rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal: Anatomy, in an anteverted and anteflexed position
  • Rectovaginal space or Douglas pouch: lowermost recess of the peritoneum Peritoneum The peritoneum is a serous membrane lining the abdominopelvic cavity. This lining is formed by connective tissue and originates from the mesoderm. The membrane lines both the abdominal walls (as parietal peritoneum) and all of the visceral organs (as visceral peritoneum). Peritoneum: Anatomy, located between the uterus Uterus The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The uterus has a thick wall made of smooth muscle (the myometrium) and an inner mucosal layer (the endometrium). The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Uterus, Cervix, and Fallopian Tubes: Anatomy and rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal: Anatomy
  • Vesicouterine pouch: shallower pouch between urinary bladder Urinary Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters (ureter), and is held there until urination. Urinary Tract: Anatomy and uterus Uterus The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The uterus has a thick wall made of smooth muscle (the myometrium) and an inner mucosal layer (the endometrium). The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Uterus, Cervix, and Fallopian Tubes: Anatomy

Structure:

  • Fundus Fundus The superior portion of the body of the stomach above the level of the cardiac notch. Stomach: Anatomy: comprises all the uterus Uterus The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The uterus has a thick wall made of smooth muscle (the myometrium) and an inner mucosal layer (the endometrium). The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Uterus, Cervix, and Fallopian Tubes: Anatomy superior to the fallopian tubes Fallopian tubes The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The fallopian tubes receive an ovum after ovulation and help move it and/or a fertilized embryo toward the uterus via ciliated cells lining the tubes and peristaltic movements of its smooth muscle. Uterus, Cervix, and Fallopian Tubes: Anatomy
  • Body: region between the fundus Fundus The superior portion of the body of the stomach above the level of the cardiac notch. Stomach: Anatomy and cervix Cervix The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Externally, the cervix is lined by stratified squamous cells; however, the cervical canal is lined by columnar epithelium. Uterus, Cervix, and Fallopian Tubes: Anatomy
  • Isthmus Isthmus Uterus, Cervix, and Fallopian Tubes: Anatomy: the narrowing at the cervix Cervix The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Externally, the cervix is lined by stratified squamous cells; however, the cervical canal is lined by columnar epithelium. Uterus, Cervix, and Fallopian Tubes: Anatomy–body transition
  • Cervix Cervix The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Externally, the cervix is lined by stratified squamous cells; however, the cervical canal is lined by columnar epithelium. Uterus, Cervix, and Fallopian Tubes: Anatomy: comprised of the internal orifice (aperture to the uterine body), cervical canal Cervical canal Uterus, Cervix, and Fallopian Tubes: Anatomy, and the external orifice ( vagina Vagina The vagina is the female genital canal, extending from the vulva externally to the cervix uteri internally. The structures have sexual, reproductive, and urinary functions and a rich blood supply, mainly arising from the internal iliac artery. Vagina, Vulva, and Pelvic Floor: Anatomy cervical canal Cervical canal Uterus, Cervix, and Fallopian Tubes: Anatomy junction)

Supporting structures:

Blood supply: 

  • Arterial:
  • Venous: Uterine veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology drain into internal iliac veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology.
Blood supply of the uterus and ovaries

Blood supply of the uterus and ovaries:
Note the ovarian artery traveling along the ovarian suspensory ligament, supplying both the ovaries as well as the lateral ⅓ of the uterine tube. The ovarian artery continues in the mesosalpinx to anastomose with branches of the uterine artery.

Image by Lecturio. License: CC BY-NC-SA 4.0

Relevant procedures

  • Cystotomy: surgical incision Surgical Incision Surgical Site Infections performed on the urinary bladder Urinary Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters (ureter), and is held there until urination. Urinary Tract: Anatomy for repair (cystoplasty), bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess laceration Laceration Torn, ragged, mangled wounds. Blunt Chest Trauma, or rupture due to trauma or a defect in the bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess wall
  • Cystectomy: surgical removal of the urinary bladder Urinary Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters (ureter), and is held there until urination. Urinary Tract: Anatomy, usually indicated by malignancy Malignancy Hemothorax
  • Urostomy: surgically made communication Communication The exchange or transmission of ideas, attitudes, or beliefs between individuals or groups. Decision-making Capacity and Legal Competence between the bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess and skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions to facilitate evacuation of bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess contents
  • Abdominal hysterectomy: surgical removal of the uterus Uterus The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The uterus has a thick wall made of smooth muscle (the myometrium) and an inner mucosal layer (the endometrium). The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Uterus, Cervix, and Fallopian Tubes: Anatomy via an infraumbilical midline laparotomy Midline Laparotomy Laparotomy and Laparoscopy
  • Cesarean delivery Cesarean Delivery Cesarean delivery (CD) is the operative delivery of ≥ 1 infants through a surgical incision in the maternal abdomen and uterus. Cesarean deliveries may be indicated for a number of either maternal or fetal reasons, most commonly including fetal intolerance to labor, arrest of labor, a history of prior uterine surgery, fetal malpresentation, and placental abnormalities. Cesarean Delivery (CD): delivery of a fetus via a horizontal incision (Pfannenstiel or Joel-Cohen)
  • Suprapubic prostatectomy Prostatectomy Complete or partial surgical removal of the prostate. Three primary approaches are commonly employed: suprapubic – removal through an incision above the pubis and through the urinary bladder; retropubic – as for suprapubic but without entering the urinary bladder; and transurethral (transurethral resection of prostate). Benign Prostatic Hyperplasia: surgical removal of the prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. via an infraumbilical midline laparotomy Midline Laparotomy Laparotomy and Laparoscopy

References

  1. Blackbourne, L. (2015). Surgical Recall. Philadelphia: Wolters Kluwer Health.
  2. Phillips, N., Hornacky, A. (2021). Berry & Kohn’s Operating Room Technique. St. Louis: Elsevier.
  3. Rothrock, J., McEwen, D. (2019). Alexander’s Care of the Patient in Surgery. St. Louis: Elsevier.

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