THE POSTERIOR AOBTA, 533 



upwards, to pass above the rectum ; when neax the anus, its terminal 

 divisions enter the walls of that intestine. 



In its course this artery gives off, at pretty regular intervals, thirteen or 

 fourteen branches, the foremost of which are the largest and longest • they 

 originate from the convexity of the artery— that is from below, and 'either 



Fig. 272. 



DISTRIBUTION OF THE SMALL MESENTERIC ARTERY; THE SMALL COLON WITH ITS 



MESENTERY IS SPREAD OUT, AND THE SMALL INTESTINE THROWN BACK TO THE ' 



RIGHT UNDER THE LARGE COLON. 



1, Trunk of the small mesenteric arteiy; 2, Great mesenteric artery; 3, Its 

 anterior fasciculus ; 4, First artery of the small colon, forming part of that 

 fasciculus ; 5, Retrograde colic artery ; 6, Right fasciculus of the great mesen- 

 teric; 7, Branches of the left fasciculus; 8, Renal artery ; 9, Terminal extremity 

 of the aorta ; 10, External iliac artery ; 11, Circumflex iliac artery ; 12, Internal 

 iliac artery. 



singly or in clusters ; the latter disposition is the most common for the first 

 four or five. They descend into the mesentery and arrive near the superior 

 curvature of the intestine, where they are disposed in the following manner; 

 The- first seven or eight bifurcate, and form arches like those of the arteries 

 supplying the small intestine, differing from them only in being nearer the, 

 37 



