

524 THE SPLEEN. 



lobus Spigelii, and the cceliac axis. And the lower border is sepa- 

 rated from the transverse portion of the duodenum by the superior 

 mesenteric artery and vein. Upon the posterior part of the head 

 of the pancreas is a lobular fold of the gland which completes the 

 canal of the superior mesenteric vessels, and is called the lesser pan- 

 creas. 



In structure it is composed of reddish-yellow angular lobules ; 

 these consist of smaller lobules, and the latter are made up of the 

 arborescent ramifications of minute ducts, terminating in csecal 

 pouches. 



The pancreatic duct commences at the papilla upon the inner and 

 posterior surface of the perpendicular portion of the duodenum by a 

 small dilatation which is common to it and to the ductus communis 

 choledochus, and passing obliquely between the mucous and muscu- 

 lar coats runs from right to left through the middle of the gland, 

 lying nearer to its anterior than to its posterior surface. At about 

 the commencement of the apicial third of its course it divides into 

 two parallel terminal branches. It gives off numerous small 

 branches, which are distributed through the lobules, and constitute 

 with the latter the substances of the gland. The duct which re- 

 ceives the secretion from the lesser pancreas is called the ductus 

 pancreaticus minor ; it opens into the principal duct near to the duo- 

 denum, and sometimes passes separately into that intestine. As a 

 variety, two pancreatic ducts are occasionally met with. 



Vessels and Nerves. The arteries of the pancreas are branches 

 of the splenic, hepatic, and superior mesenteric ; the veins open into 

 the splenic vein; the lymphatics terminate in the lumbar glands. 

 The nerves are filaments of the splenic plexus. 



THE SPLEEN. 



The spleen is an oblong flattened organ of a dark bluish-red co- 

 lour, situated in the left hypochondriac region. It is very variable 

 in size and weight, spongy and vascular in texture and exceedingly 

 friable. The external surface is convex, the internal slightly con- 

 cave, indented along the middle line, and pierced by several large 

 and irregular openings for the entrance and exit of vessels ; this is 

 the hilus lienis. The upper extremity is somewhat larger than the 

 lower, and rounded ; the inferior is flattened ; the posterior border 

 is obtuse ; the anterior is sharp and marked by several notches. 

 The spleen is in relation by its external or convex surface with the 

 diaphragm, which separates it from the ninth, tenth, and eleventh 

 ribs ; by its concave surface with the great end of the stomach, the 

 extremity of the pancreas, the gastro-splenic omentum with its ves- 

 sels, the left kidney and supra-renal capsule, and with the left crus 

 of the diaphragm ; by its upper end with the diaphragm, and some- 

 times with the extremity of the left lobe of the liver, and by its lower 

 end with the left extremity of the transverse arch of the colon. It 

 is connected to the stomach by the gastro-splenic omentum and by 



