Atlas of Anatomy
13 Internal Organs
Fig. 13.1 Stomach: Location
Fig. 13.2 Surfaces of the stomach
Fig. 13.3 Stomach
The stomach is found in the right and left upper quadrants. It is intraperitoneal, its mesenteries being the lesser and greater omenta.
Fig. 13.4 Stomach in situ
Anterior view of the opened upper abdomen. Arrow indicates the omental foramen.
Gastritis and gastric ulcers
Gastritis and gastric ulcers, the two most common diseases of the stomach, are associated with increased acid production and are caused by alcohol, drugs such as aspirin, and the bacterium Helicobacter pylori. Symptoms include lessened appetite, pain, and even bleeding, which manifests as black stool or dark brown material in vomit. Gastritis is limited to the inner surface of the stomach, while gastric ulcers extend into the stomach wall. The gastric ulcer in C is covered with fibrin and shows hematin spots.
The small intestine consists of the duodenum, jejunum, and ileum (see p. 162). The duodenum is primarily retroperitoneal and divided into four parts: superior, descending, horizontal, and ascending.
Fig. 13.5 Duodenum: Location
Fig. 13.6 Parts of the duodenum
Fig. 13.7 Duodenum
Anterior view with the anterior wall opened.
Fig. 13.8 Duodenum in situ
Anterior view. Removed: Stomach, liver, small intestine, and large portions of the transverse colon. Thinned: Retroperitoneal fat and connective tissue.
Endoscopy of the papillary region
Two important ducts end in the papillary region of the duodenum: the common bile duct and the pancreatic duct (see Fig. 13.7). These ducts may be examined by X-ray through endoscopic retrograde cholangiopancreatography (ERCP), in which dye is injected endoscopically into the duodenal papilla. Duodenal diverticula (generally harmless outpouchings) may complicate the procedure.
Jejunum & Ileum
Fig. 13.9 Jejunum and ileum: Location
Anterior view. The intraperitoneal jejunum and ileum are enclosed by the mesentery proper.
Fig. 13.10 Wall structure of the small intestine
Macroscopic views of the longitudinally opened small intestine.
Fig. 13.11 Jejunum and ileum in situ
Anterior view. Reflected: Transverse colon.
Crohn's disease, a chronic inflammation of the digestive tract, occurs most often in the terminal ileum (30% of cases). Patients are generally young and suffer from abdominal pain, nausea, elevated body temperature, and diarrhea. Initially, these symptoms can be confused with appendicitis. Complications of Crohn's disease often include anal fistulae (B).
Fig. 13.12 Mesentery of the small intestine
Anterior view. Removed: Stomach, jejunum, and ileum. Reflected: Liver.
Cecum, Appendix & Colon
The large intestine consists of the cecum, appendix, colon, and rectum (see p. 166). The colon is divided into four parts: ascending, transverse, descending, and sigmoid. The appendix, transverse colon, and sigmoid colon are intraperitoneal (suspended by the mesoappendix, transverse mesocolon, and sigmoid mesocolon, respectively).
Fig. 13.13 Large intestine: Location
Fig. 13.14 Ileocecal orifice
Anterior view of longitudinal coronal section.
Fig. 13.15 Large intestine
Fig. 13.16 Large intestine in situ
Ulcerative colitis is a chronic inflammation of the large intestine, often starting in the rectum. Typical symptoms include diarrhea (sometimes with blood), pain, weight loss, and inflammation of other organs. Patients are also at higher risk for colorectal carcinomas.
Malignant tumors of the colon and rectum are among the most frequent solid tumors. More than 90% occur in patients over the age of 50. In early stages, the tumor may be asymptomatic; later symptoms include loss of appetite, changes in bowel movements, and weight loss. Blood in the stools is particularly incriminating, necessitating a thorough examination. Hemorrhoids are not a sufficient explanation for blood in stools unless all other tests (including a colonoscopy) are negative.
Rectum & Anal Canal
Fig. 13.17 Rectum: Location
Fig. 13.18 Closure of the rectum
Left lateral view. The puborectalis acts as a muscular sling that kinks the anorectal junction. It functions in the maintenance of fecal continence.
Fig. 13.19 Rectum in situ
Coronal section, anterior view of the female pelvis. The upper third of the rectum is covered with visceral peritoneum on its anterior and lateral sides. The middle third is covered only anteriorly and the lower third is inferior to the parietal peritoneum.
Fig. 13.20 Rectum and anal canal
Coronal section, anterior view with the anterior wall removed.
Fig. 13.21 Liver: Location
Fig. 13.22 Liver in situ
Anterior view with liver retracted. Removed: Stomach, jejunum, and ileum. The liver is intraperitoneal except for its “bare area” (see Fig. 13.26); its mesenteries include the falciform, coronary, and triangular ligaments (See Fig. 13.27).
Fig. 13.23 Abdominal MRI
Liver: Segments & Lobes
Fig. 13.24 Segmentation of the liver
Anterior view. The components portal triad (hepatic artery, portal vein, and hepatic duct, see pp. 172, 219) divides the liver into hepatic segments (see Table 13.2).
Fig. 13.25 Liver: Areas of organ contact
Visceral surface, inferior view.
Fig. 13.26 Attachment of liver to diaphragm
Fig. 13.27 Surfaces of the liver
The liver is divided by its ligaments into four lobes: right, left, caudate, and quadrate.
Gallbladder & Bile Ducts
Fig. 13.28 Gallbladder: Location
Fig. 13.29 Hepatic bile ducts: Location
Projection onto surface of the liver, anterior view.
Fig. 13.30 Biliary sphincter system
Fig. 13.31 Extrahepatic bile ducts
Anterior view. Opened: Gallbladder and duodenum.
Fig. 13.32 Biliary tract in situ
Anterior view. Removed: Stomach, small intestine, transverse colon, and large portions of the liver. The gallbladder is intraperitoneal, covered by visceral peritoneum where it is not attached to the liver.
Obstruction of the bile duct
As bile is stored and concentrated in the gallbladder, certain substances, such as cholesterol, may crystallize, resulting in the formation of gallstones. Migration of gallstones into the bile duct causes severe pain (colic). Gallstones may also block the pancreatic duct in the papillary regions, causing highly acute or even life-threatening pancreatitis.
Ultrasound appearance of two gallstones. Black arrows mark the echo-free area behind the stones.
Pancreas & Spleen
Fig. 13.33 Pancreas and spleen: Location
Fig. 13.34 Pancreas
Anterior view with dissection of the pancreatic duct.
Fig. 13.35 Spleen
Fig. 13.36 Pancreas and spleen in situ
Anterior view. Removed: Liver, stomach, small intestine, and large intestine. The pancreas is retroperitoneal, while the spleen is intraperitoneal.
Fig. 13.37 Pancreas and spleen: Transverse section
Inferior view. Section through L1 vertebra.
Kidneys & Suprarenal Glands: Overview
Fig. 13.38 Kidneys and suprarenal glands: Location
Fig. 13.39 Kidneys: Areas of organ contact
Fig. 13.40 Right kidney in the renal bed
Sagittal section through the right renal bed.
Fig. 13.41 Suprarenal gland
Fig. 13.42 Kidneys and suprarenal glands in the retroperitoneum
Anterior view. Both the kidneys and suprarenal glands are retroperitoneal.
Kidneys & Suprarenal Glands: Features
Fig. 13.43 Right kidney and suprarenal gland
Anterior view. Removed: Perirenal fat capsule. Retracted: Inferior vena cava.
Fig. 13.44 Left kidney and suprarenal gland
Anterior view. Removed: Perirenal fat capsule. Retracted: Pancreas.
Fig. 13.45 Kidney: Structure
Right kidney with suprarenal gland.
The ureters cross the common iliac artery at its bifurcation into the external and internal iliac arteries.
Fig. 13.46 Ureters: Location
Fig. 13.47 Ureters in situ
Anterior view, male abdomen. Removed: Nonurinary organs and rectal stump. The ureters are retroperitoneal.
Fig. 13.48 Ureter in the male pelvis
Fig. 13.49 Ureter in the female pelvis
Fig. 13.50 Male urinary bladder
The urinary bladder is retropubic and retroperitoneal in location.
Fig. 13.51 Female urinary bladder
Urinary Bladder & Urethra
Fig. 13.52 Female urinary bladder and urethra
Midsagittal section, viewed from the left side.
Fig. 13.53 Male urinary bladder and urethra
Midsagittal section, viewed from the left side.
Fig. 13.54 Wall structure
Anterior view of coronal section.
Fig. 13.55 Urinary bladder and urethra