THE SPLEEN. 



1353 



o-astric, and renal surfaces ; anterior, at the junction of the diaphragmatic, gastric, and 

 basal surfaces ; posterior, at ,the junction of the diaphragmatic, renal, and basal surfaces ; 

 intermediate, at the junction of the renal, gastric, and basal surfaces. In a spleen of 

 orange-segment form there are but two angles, a superior and an anterior. The superior 

 is bounded in the same way as in the tetrahedral form ; the anterior, by the dia- 

 phragmatic, gastric, and renal surfaces. In all spleens, but most commonly in those of 

 oblique, irregularly tetrahedral form, the superior angle may curve forward as a blunt 

 hook. 



The spleen is entirely covered with peritoneum and is moored by two peritoneal folds, 

 the lieno-renal and gastro-splenic ligaments (pp. 1162 and 1236). Inferiorly it is supported 

 by the peritoneal phrenico-colic ligament (p. 1242). 



Rib IX 



RibX 



Rib XI 



Descending colon 



Rib IX 



RibX 



Rib XI 



Ascending colon 



FIG. 1062. DISSECTION OF THE SPLEEN, LIVER, AND KIDNEYS FROM BEHIND, IN A SUBJECT HARDENED BY 



FORMALIN-INJECTION. 



Small globular accessory spleens are often present. As a rule they are attached to 

 the gastro-splenic ligament near the splenic hilum. 



Blood and Lymph Vessels. The spleen receives its- blood from the splenic artery, which 

 passes through the lieno-renal ligament. Before reaching the gland it breaks up into six or 

 more branches which enter the hilum independently. The vein of the spleen, the splenic vein, 

 is formed in the lieno-renal ligament by the union of several unnamed tributaries which emerge 

 from the hilum. The lymph vessels also leave the spleen at the hilum. They are small and come 

 from the capsule and trabeculse only, not from the glandular part of the organ. 



Nerves. The nerves are almost entirely non-medullated and come from the cceliac plexus. 

 They accompany the splenic artery and its branches. 



Structure. The spleen is composed of a soft substance called pulp, supported by fibrous 

 trabeculee and enclosed within a fibrous capsule, tunica propria, which, in turn, is enclosed within 

 a peritoneal capsule, tunica serosa. Embedded in the pulp are nodules of lymph tissue, noduli 

 lymphatici lienales (O.T. Malpighian corpuscles). 



The tunica serosa closely invests the organ, except where it is reflected on to the lieno-renal 

 and gastro-splenic ligaments and at the hilum. It is very firmly bound to the tunica propria. 



The tunica propria is stout and strong but highly elastic. It is composed mainly of fibrous 



