THE ARTERIES. 301 



also sends branches onto the dorsum of the hand at the sides 

 of the fourth metacarpal. Branches pass from these proximad 

 to the wrist. 



B. AORTA ABDOMINALIS. THE ABDOMINAL AORTA. 

 The abdominal aorta emerges into the abdomen from between 

 the crura of the diaphragm, at about the 

 level of the second lumbar vertebra. It 

 passes caudad along the dorsal middle 

 line, lying to the left of the inferior vena 

 cava. It gives off parietal branches to 

 the body wall, and visceral branches to 

 the viscera, and ventrad of the first sacral 

 vertebra it gives off two large branches on 

 each side, the external iliac (Fig. 126, k) 

 and the hypogastric (Fig. 126, /) a very 

 small median vessel, the sacralis media 

 (Fig. 126, o), continuing the course of the THE PA^AR'ARCH AND 

 aorta and passing into the tail. ITS BRANCHES IN THE 



. . rr ^i r 11 PALM OF THE HAND. 



The aorta gives off the following The interosseous mus . 



branches: A. coeliaca; A. mesenterica cies have been removed, 

 superior; Aa. adrenolumbales ; Aa. re- l^^^ ^ 

 nales; A. mesenterica inferior; Aa. ilio- abductor digit! quinti; 2, 



,,. . , , , \ 3- M m - interossei of third 



lumbales; Aa. lumbales (seven pairs); and fourth d jgj ts . 4? M. 

 Aa. iliacae externae ; Aa. hypogastricae. adductor poiiids; 5, M. 



" flexor brevis polhcis. a, 



A. A. COeliaCa (Fig. 125). - Thecoeliac termination of radial artery; 



artery is a large branch which is given off *> palmar arch; f, A. prin- 



ceps pollicis et mdicis; a, 

 from the aorta one centimeter or less Aa. interossese; e, muscu- 



caudad of the opening in the diaphragm. 



It passes directly ventrad about three or mar branch of ulnar nerve. 



four centimeters, then divides, usually at once, into three 

 branches. The most cranial of these is the hepatic (d^, the 

 next is the gastrica sinistra (e), while the third and largest, 

 seeming to form a continuation of the cceliac, is the splenic (/) 

 (A. lienalis). The coeliac artery may give rise also, before its 

 division, to the two phrenic arteries (which, however, usually 

 arise from the adrenolumbales), and either before or at the point 

 of division to one or two small Aa. ventriculi dorsales, which, 

 however, frequently arise from the gastrica sinistra. 



