Atlas of Anatomy

13 Internal Organs

Stomach

Fig. 13.1   Stomach: Location

image

Fig. 13.2   Surfaces of the stomach

image

Fig. 13.3   Stomach
Anterior view.

image

image 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.

image

image Clinical

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.

image

Duodenum

image 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
Anterior view.

image

Fig. 13.6   Parts of the duodenum
Anterior view.

image

Fig. 13.7   Duodenum
Anterior view with the anterior wall opened.

image

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.

image

image Clinical

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.

image

Jejunum & Ileum

Fig. 13.9   Jejunum and ileum: Location
Anterior view. The intraperitoneal jejunum and ileum are enclosed by the mesentery proper.

image

Fig. 13.10   Wall structure of the small intestine
Macroscopic views of the longitudinally opened small intestine.

image

Fig. 13.11   Jejunum and ileum in situ
Anterior view. Reflected: Transverse colon.

image

image Clinical

Crohn's disease

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).

image

Fig. 13.12   Mesentery of the small intestine
Anterior view. Removed: Stomach, jejunum, and ileum. Reflected: Liver.

image

Cecum, Appendix & Colon

image 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
Anterior view.

image

Fig. 13.14   Ileocecal orifice
Anterior view of longitudinal coronal section.

image

Fig. 13.15   Large intestine
Anterior view.

image

Fig. 13.16   Large intestine in situ

image

image Clinical

Colitis

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.

Colon carcinoma

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.

image

Rectum & Anal Canal

Fig. 13.17   Rectum: Location

image

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.

image

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.

image

Fig. 13.20   Rectum and anal canal
Coronal section, anterior view with the anterior wall removed.

image

image

Liver: Overview

Fig. 13.21   Liver: Location

image

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).

image

Fig. 13.23   Abdominal MRI
Inferior view.

image

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. 172219) divides the liver into hepatic segments (see Table 13.2).

image

Fig. 13.25   Liver: Areas of organ contact
Visceral surface, inferior view.

image

Fig. 13.26   Attachment of liver to diaphragm

image

image

Fig. 13.27   Surfaces of the liver
The liver is divided by its ligaments into four lobes: right, left, caudate, and quadrate.

image

Gallbladder & Bile Ducts

Fig. 13.28   Gallbladder: Location

image

Fig. 13.29   Hepatic bile ducts: Location
Projection onto surface of the liver, anterior view.

image

Fig. 13.30   Biliary sphincter system

image

Fig. 13.31   Extrahepatic bile ducts
Anterior view. Opened: Gallbladder and duodenum.

image

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.

image

image Clinical

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.

image

Ultrasound appearance of two gallstones. Black arrows mark the echo-free area behind the stones.

Pancreas & Spleen

Fig. 13.33   Pancreas and spleen: Location

image

Fig. 13.34   Pancreas
Anterior view with dissection of the pancreatic duct.

image

Fig. 13.35   Spleen

image

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.

image

Fig. 13.37   Pancreas and spleen: Transverse section
Inferior view. Section through L1 vertebra.

image

Kidneys & Suprarenal Glands: Overview

Fig. 13.38   Kidneys and suprarenal glands: Location

image

Fig. 13.39   Kidneys: Areas of organ contact
Anterior view.

image

Fig. 13.40   Right kidney in the renal bed
Sagittal section through the right renal bed.

image

Fig. 13.41   Suprarenal gland
Anterior view.

image

Fig. 13.42   Kidneys and suprarenal glands in the retroperitoneum
Anterior view. Both the kidneys and suprarenal glands are retroperitoneal.

image

Kidneys & Suprarenal Glands: Features

Fig. 13.43   Right kidney and suprarenal gland
Anterior view. Removed: Perirenal fat capsule. Retracted: Inferior vena cava.

image

Fig. 13.44   Left kidney and suprarenal gland
Anterior view. Removed: Perirenal fat capsule. Retracted: Pancreas.

image

Fig. 13.45   Kidney: Structure
Right kidney with suprarenal gland.

image
image

Ureter

image The ureters cross the common iliac artery at its bifurcation into the external and internal iliac arteries.

Fig. 13.46   Ureters: Location
Anterior view.

image

Fig. 13.47   Ureters in situ
Anterior view, male abdomen. Removed: Nonurinary organs and rectal stump. The ureters are retroperitoneal.

image

Fig. 13.48   Ureter in the male pelvis
Superior view.

image

Fig. 13.49   Ureter in the female pelvis
Superior view.

image

Urinary Bladder

Fig. 13.50   Male urinary bladder

image

image The urinary bladder is retropubic and retroperitoneal in location.

Fig. 13.51   Female urinary bladder

image

Urinary Bladder & Urethra

Fig. 13.52   Female urinary bladder and urethra
Midsagittal section, viewed from the left side.

image

Fig. 13.53   Male urinary bladder and urethra
Midsagittal section, viewed from the left side.

image

Fig. 13.54   Wall structure
Anterior view of coronal section.

image

Fig. 13.55   Urinary bladder and urethra
Anterior view.

image