Fig. 15.1 Gaster: Location
The gaster resides primarily in the left upper quadrant. It is intraperitoneal, its mesenteria being the omenta minus and majus.
Fig. 15.4 Gaster in situ
Anterior view of the opened upper abdomen. Arrow indicates the foramen omentale.
Gastritis and gastric ulcers
Gastritis and gastric ulcers, the two most common diseases of the gaster, 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, often described as resembling “coffee grounds,” in vomit. Gastritis is limited to the inner surface of the gaster, whereas gastric ulcers extend into the gastric wall. The gastric ulcer in C is covered with fibrin and shows hematin spots.
The intestinum tenue consists of the duodenum, jejunum, and ileum (see p. 168). The duodenum is primarily retroperitoneal and is divided into four parts: partes superior, descendens, horizontalis (inferior), and ascendens.
Fig. 15.8 Duodenum in situ
Anterior view. Removed: Gaster, hepar, intestinum tenue, and large portions of the colon transversum. Thinned: Retroperitoneal fat and connective tissue.
Endoscopy of the papillary region
Two important ducts end in the pars descendens of the duodenum: the ductus choledochus and the ductus pancreaticus (see Fig. 15.7). These ducts may be examined by X-ray through endoscopic retrograde cholangiopancreatography (ERCP), in which dye is injected endoscopically into the papilla duodeni major. Duodenal diverticula (generally harmless outpouchings) may complicate the procedure.
Fig. 15.9 Jejunum and ileum: Location
Anterior view. The intraperitoneal jejunum and ileum are enclosed by the mesenterium proper.
Fig. 15.10 Wall structure of the jejunum and ileum
Macroscopic views of the longitudinally opened intestinum tenue.
Crohn's disease
Crohn's disease, a chronic inflammation of the digestive tract, occurs most often in the pars terminalis ilei (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 the chronic inflammation in Crohn's disease often lead to fistula formation (in this case, an abnormal passage between two gastrointestinal regions) (B).
Fig. 15.12 Mesenterium of the intestinum tenue
Anterior view. Removed: Gaster, jejunum, and ileum. Reflected: Hepar.
The cola ascendens and descendens are normally secondarily retroperitoneal, but sometimes they are suspended by a short mesenterium from the posterior abdominal wall. Note: In the clinical setting, the flexura coli sinistra is often referred to as the flexura coli splenica and the flexura coli dextra, as the flexura coli hepatica.
Fig. 15.16 Intestinum crassum in situ
Anterior view. Reflected: Colon transversum and omentum majus. Removed: Intraperitoneal intestinum tenue.
Colitis
Ulcerative colitis is a chronic inflammation of the intestinum crassum, 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.
Fig. 15.18 Hepar in situ
Anterior view. The hepar is intraperitoneal except for its area nuda (see Fig. 15.23); its mesenteria include the ligg. falciforme, coronarium, and triangularia (see Fig. 15.22A).
Fig. 15.19 Hepar in situ: Facies visceralis (visceral surface)
The hepar is retracted to show the vesica biliaris on its facies visceralis.
Fig. 15.22 Surfaces of the hepar
The hepar is divided into four lobi by its ligaments: lobus hepatis dexter, lobus hepatis sinister, lobus caudatus, and lobus quadratus. The lig. falciforme, a double layer of peritoneum parietale that reflects off the anterior abdominal wall and extends to the hepar, spreading out over its surface as peritoneum viscerale, divides the hepar into lobus dexter and lobus sinister. The lig. teres hepatis is found in the free edge of the lig. falciforme and is the obliterated v. umbilicalis, which once extended from the umbilicus to the hepar.
Fig. 15.23 Segmentation of the hepar
The hepar is divided into functional divisiones, which are further divided into segmenta (see Table 15.1). Each segmentum is served by tertiary branches of the a. hepatica propria, the v. portae hepatis, and the ductus hepaticus communis, which together make up the trias hepatica.
Fig. 15.28 Biliary tract in situ
Anterior view. Removed: Gaster, intestinum tenue, colon transversum, and large portions of the hepar. The vesica biliaris is intraperitoneal, covered by peritoneum viscerale where it is not attached to the hepar.
Obstruction of the ductus choledochus
As bile is stored and concentrated in the vesica biliaris, certain substances, such as cholesterol, may crystallize, resulting in the formation of gallstones. Migration of gallstones into the ductus choledochus causes severe pain (colic). Gallstones may also block the ductus pancreaticus in the papillary regions, causing highly acute or even life-threatening pancreatitis.
Fig. 15.32 Pancreas and splen in situ
Anterior view. Removed: Hepar, gaster, intestinum tenue, and intestinum crassum. The pancreas is retroperitoneal, whereas the splen is intraperitoneal.
Fig. 15.37 Renes and glandulae suprarenales in the retroperitoneum
Anterior view. Both the renes and gll. suprarenales are retroperitoneal.
Clinical box 15.1
