THE STOMACH
The stomach is of the simple type, presenting fundus, corpus, and a pyloric part (Figure 34-4/2). The first two are generally confined to the left side of the abdomen but may extend across the median plane when the stomach is grossly distended.
They are cranially related to the liver and diaphragm. The pyloric part extends to the right and is also in contact with the liver. All parts are related caudally to various parts of the intestinal mass; the principal relation is to the ascending colic spiral. It is only when grossly distended that the stomach makes contact with the abdominal floor and, on the left, extends beyond the protection of the rib cage. A feature unique to the pig among domestic species is the presence of a conical diverticulum (Figure 34-5/2) projecting caudally from the fundus.The interior displays a narrow nonglandular strip of mucosa that extends into the diverticulum and follows the lesser curvature for some distance below the cardia (Figure 34-5/7). The remainder of the mucosa is divided into the usual three glandular regions, which are more clearly distinguished by color than in most species, although their borders are not always sharply defined (Figure 34-5∕2α, 2b, 2c). A second feature of distinction is the very prominent torus narrowing the pyloric canal at the exit into the duodenum (Figure 34-4/70).
Although the omenta are arranged much as in the dog, the greater one is less extravagantly developed, does not intervene between the intestines and the abdominal floor, and is therefore not encountered when the abdomen is first opened (Figure 33-4/5).