The Spleen is one of the abdominal organs, but not connected with digestion. It is the largest of the ductless glands.

It lies in the left hypochondrium in the mid-axillary line reaching from the upper border of the ninth rib to the upper border of the twelfth, its long axis being in the same direction as that of the tenth rib. It has an irregular shape. The outer surface is convex and more or less oval, and closely applied to the diaphragm which separates it from the ribs. The visceral surface is divided into three parts by ridges, which join to form a more or less prominent apex in the centre. The upper and largest part has a deep concave impression formed by the stomach; the two lower parts are in contact respectively with the left kidney and the splenic flexure of the colon. At the lower border of the gastric impression is the hilus, where the bloodvessels and nerves enter, and just below this is the impression made by the tail of the pancreas.

The spleen is almost completely covered by peritoneum, and two folds pass from it connecting it with the stomach and kidney, called, respectively, the gastro-splenic and lieno-renal ligaments.

Fig. 50. - The Spleen.