482 ABDOMEN 



leave the vessels and effect a series of communications, with 

 each other, in the intervals between the arteries. 



The superior mesenteric plexus is an offshoot from the 

 cceliac plexus, and it distributes twigs to the jejunum, ileum, 

 and to the right half of the great intestine. 



Lymphoglandulse Mesentericse. The mesenteric lymph 

 glands are very numerous, indeed considerably over a 

 hundred in number. In health they rarely attain a size 

 greater than that of a small bean or a pea, and they are 

 scattered between the two layers of the mesentery. The 

 larger glands lie along the superior mesenteric artery, whilst 

 the others are placed in the intervals between its branches. 

 It should be noted that they are most numerous opposite the 

 jejunum, and that the mesentery in the immediate vicinity of 

 the intestine is free from them. 



A few lymph glands will also be noticed in connection 

 with the large intestine. 



The lacteal vessels enter the mesentery from the walls of 

 the intestine in enormous numbers. As they proceed up- 

 wards they pass through the succession of glands which they 

 meet, and, greatly reduced in number although considerably 

 enlarged in calibre, they usually terminate, near the origin of 

 the superior mesenteric artery, in one or perhaps more trunks 

 which pour their contents into the cisterna chyli of the 

 thoracic duct. 



Arteria Mesenterica Inferior. The inferior mesenteric 

 artery, considerably smaller than the superior mesenteric, 

 springs from the left side of the front of the abdominal aorta, 

 about an inch and a half above its termination. It descends, 

 with a slight inclination to the left, to the brim of the pelvis, 

 there it crosses to the left common iliac artery and becomes 

 the superior hcemorrhoidal which descends into the pelvis. 

 Before it reaches the left common iliac artery it gives off the 

 left colic and the sigmoid branches. 



The Arteria Colica Sinistra. The left colic artery runs 

 to the left and divides into two branches, of which one 

 ascends in front of the lower part of the left kidney to the 

 transverse meso-colon where it inosculates with the middle 

 colic, whilst the other descends behind the peritoneum of 

 the posterior wall of the abdomen, to unite with the superior 

 sigmoid artery. From the arches thus formed twigs are 

 supplied to the transverse colon, the left colic flexure, and 



