INFERIOR MESENTERIC— MIDDLE SACRAL 



563 



of till' internal spliineter, wIktc, l)y their anastomosis, they form a series of loops 

 an^und the lower }tart of the reetum. 



The chief variations in the inferior mesenteric arc : — (A) Its place may be supplied by the 

 superior meseutcric. (1>) It may give branches tu the liver or kiduey. (C) It may give off the 



Fig. 367. — Thk Inferior Mesknteric Artery and Veix. 

 (The colon is turned up, aud the small iutestines are drawn to the right side.) 



Middle colic arlerti — 



Inferior pancreatico- 

 duodenal artery 

 Superior mesenteric 

 artery 

 Riijht colic artery 



Abdominal aorta 

 Vena cava inferior 



Right common iliac 



artery 



Middle sacral artery 



and vein 



Left colic artery 



Inferior mesenteric 

 vein 



Inferior nn'senleric 



uriery 

 Left colic artery 



Inferior vifsenteric 



artery 



Left common iliac 

 rem 



■'iiymoid artery 



Superior htemor- 

 r/ioidai artery 



middle colic. (D) It may give off a stem to both umbilical arteries. (E) The anastomosis between 

 the middle aud left colic arteries maybe wanting — the normal condition in the rumiiianls and the 

 porcupines. 



C. The Terminat. Branches of the Aedomixae Aorta 



THE MIDDLE SACRAL ARTERY 



The middle sacral artery is, anatomically, the continuation of the aorta, and 

 is generally l)nt not universally held to be the homologue of the sacral and coccygeal 

 aorta of some animals. The so-called coccygeal glomerulus, or Luschka's gland, in 

 Avhich it terminates, is l:)elieved to contain the rudiments of the caudal aorta, or 

 artery of the tail. The artery is mesially j)laced, and extends from the bifurcation 

 of the aorta to the tip of the coccyx. As itj^asses downwards into the pelvis, it runs 

 behind the left common iliac vein, the hypogastric plexus of the syinjiathetic nerve, 

 and the layer of peritoneum that descends from the mesentery into the pelvis to 

 become the meso-rectum. It lies successively upon the intervertebral disc between 

 the fourth and fifth lumbar vertebrae, the fifth lumbar vertel)ra, the intervertebral 

 disc between that vertel)ra and the sacrum, and lower down upon the middle of 

 the anterior surface of the sa(,-rum and coccvx. 



