The Stomach and Spleen. 183 



3. Working on the left side between the dorsal surface of the 

 stomach and the body-wall, remove sufficient of the peritoneum to 

 expose the first portion of the abdominal aorta as it emerges from 

 the diaphragm. Passing in the direction of the stomach is a 

 median ventral branch, the coeliac artery, the distribution of 

 which may be traced. The following structures, however, should 

 first be identified, especially the ganglia (d, e) which are likely to 

 be damaged in disturbing the peritoneum. 



(a) The superior mesenteric artery (a. mesenterica superior), 

 a second, also much larger, median branch of the aorta, given 

 off a little distance behind the coeliac artery and passing in 

 the direction of the intestine. 



(b) The suprarenal gland (gl. suprarenalis) of the left side, a 

 yellowish bean-shaped body of about half an inch in length, 

 to the medial side of the anterior part of the kidney. 



(c) The inferior caval vein (v. cava inferior), a large thin- 

 walled vessel lying to the right of the aorta. It is not 

 conspicuous if empty. 



(d) The coeliac ganglion (g. coeliacum) of the sympathetic 

 nervous system lies in front of the superior mesenteric artery. 



(e) The superior mesenteric ganglion (g. mesentericum 

 superius) of the sympathetic system lies immediately behind 

 the superior mesenteric artery, and also on its lateral walls. 

 The two ganglia are connected by nerves which cross the 

 superior mesenteric artery. 



(f) The nerves proceeding from the coeliac and superior mesen- 

 teric ganglia accompany the corresponding arteries, forming 

 the coeliac and superior mesenteric plexuses. 



(g) The (greater) splanchnic nerve (n. splanchnicus major) of 

 the left side passes backward from its origin in the thorax 

 (see p. 264), around the reduced left crus of the diaphragm, 

 and crossing the aorta obliquely enters the superior mesen- 

 teric ganglion. 



(h) A portion of the pancreas (cf. p. 189) is seen in the peri- 

 toneum after the branches of the splenic artery have been 

 severed (4, a). 



4. Trace the plan of branching of the coeliac artery, beginning 

 at the point of origin, and exposing the vessels in order. 



