304 THE CIRCULATORY SYSTEM. 
descending portions of the large intestine. It divides and sends 
branches in both directions which anastomose with the colica 
dextra and with branches from the inferior mesenteric arteries. 
3. A. colica dextra.—A small branch which passes to the 
ascending and transverse colon, anastomosing with the colica 
media and ileocolica. It is sometimes absent. 
4. A. ileocolica.—This passes to the czcum and supplies 
that structure, sending branches to the ileocolic valve and the 
caudal end of the ileum, and anastomosing with the colica 
dextra and the intestinal branches of the superior mesenteric. 
5. The superior mesenteric now divides into about sixteen 
terminal branches which pass to the small intestine. In many 
cases these branches unite near the intestine, forming arches, 
and from these arches numerous short branches pass to the 
intestine. 
3. A. adrenolumbalis (or lumboabdominalis) (Fig. 126, ¢). 
—tThis rises from the aorta, one on each side, about two 
centimeters caudad of the superior mesenteric. Each passes 
laterad onto the dorsal body wall, supplying the muscles of this 
region. A large branch passes caudad along the surface of the 
muscles dorsad of the kidney and anastomoses with the ilio- 
lumbar artery. From the adrenolumbalis rises usually: 
A. phrenica (/).—The phrenic artery rises either from the 
cceliac (c) or the adrenolumbalis (e) and passes to the dia- 
phragm, near its dorsal border. In the diaphragm it passes 
ventrad, lying at the medial margin of the costal portion of the 
diaphragm, as far as its sternal portion, where it unites with the 
artery of the opposite side. The two thus form an arch, from 
which radiating arteries pass off to supply the diaphragm. 
4. A. renalis (¢).—The two renal arteries arise from the 
sides of the aorta, usually at about the same point,’ so that the 
left passes caudolaterad and the right craniolaterad (owing to 
the position of the kidneys). The artery usually divides just 
before entering the kidney (2). It passes dorsad of the vein 
(2). The renal artery sometimes sends a branch to the supra- 
renal body (1). It also occasionally gives origin to the ‘sper- 
matic artery (%).’ 
5. A. spermatica interna (Z).—This rises from the aorta 
