THE SPLEEN. 



949 



THE SPLEEN. 



The Spleen belongs to that class of bodies which are known as ductless glands. 



is probably related to the blood-vascular system, but in consequence of its 

 anatomical relationship to the stomach and its physiological relationship to the 

 liver it is convenient to describe it in this place. It is situated principally in the 

 left hypochondriac region, its upper and inner extremity extending into the epigas- 

 tric region ; lying between the fundus of the stomach and the Diaphragm. It is 

 the largest of the ductless glands, and measures' some five or six inches in length. 

 It is of an oblong, flattened form, soft, of very brittle consistence, highly vascular, 

 and of a dark purplish color. 



Surfaces. The external or phrenic surface is convex, smooth, and is directed 

 upward, backward, and to the left, except at its upper end, where it is directed 

 slightly inward. It is in relation with the under surface of the Diaphragm, which 

 separates it from the eighth, ninth, tenth, 

 and eleventh ribs of the left side, and in 

 part from the lower border of the left lung 

 and pleura. 



The internal surface is concave, and 

 divided by a ridge into an anterior or 

 larger, and a posterior or smaller portion. 



The anterior portion of the internal 

 surface or gastric surface, which is directed 

 forward and inward, is broad and concave, 

 and is in contact with the posterior wall 

 of the great end of the stomach ; and 

 below this with the tail of the pancreas. 

 It presents near its inner border a long 

 fissure, termed the hilum. This is pierced 

 by several irregular apertures, for the 

 entrance and exit of vessels and nerves. 



The posterior portion of the internal 

 surface or renal surface is directed inward 

 and downward. It is somewhat flattened, 

 does not reach as high as the gastric sur- 

 face, is considerably narrower than the 

 latter, and is in relation with the upper 

 part of the outer surface of the left kidney 

 and occasionally with the left suprarenal 

 capsule. 



The upper end is directed inward, toward the vertebral column, where it lies 

 on a level with the eleventh dorsal vertebra. The lower end, sometimes termed 

 the basal surface, is flat, triangular in shape, and rests upon the splenic flexure of 

 the colon and the phreno-colic ligament, and is generally in contact with the tail 

 of the pancreas. The anterior border is free, sharp, and thin, and is often notched, 

 especially below. It separates the phrenic from the gastric surface. The posterior 

 border is more rounded and blunter than the anterior. It separates the renal por- 

 tion of the internal surface from the phrenic surface. It corresponds to the lower 

 border of the eleventh rib and lies between the Diaphragm and left kidney. The 

 internal border is the name sometimes given to the ridge which separates the renal 

 and gastric portions of the internal surface. 



The spleen is almost entirely surrounded by peritoneum, which is firmly adher- 

 ent to its capsule, and is held in position by two folds of this membrane : one, 

 the lieno-renal ligament, is derived from the layers of peritoneum forming the 

 greater and lesser sacs, where they come into contact between the left kidney and 

 the spleen. BetAveen its two layers the splenic vessels pass (Fig. 489) ; the second, 

 the g astro-splenic omentum, also formed of two layers, derived from the greater 



FIG. 522. The spleen, showing its gastric and 

 renal surfaces. (Testut.) 



