THE ARTERIES 



629 



The posterior mesenteric artery arises near the termination of the aorta. It 

 is small and is distributed like that of the ox. 



Six pairs of lumbar arteries arise from the aorta. The seventh comes from 

 the middle sacral. 



The terminal branches of the aorta resemble those of the ox. 



The arteries of the shoulder,, arm, and forearm resemble in general those of 

 the ox. 



The main facts as to the metacarpal and digital arteries are as follows: The 

 rete carpi dorsale is formed essentially l)y the terminals of the interosseous artery 

 of the forearm. It gives rise to three dorsal metacarpal arteries which descend in 



Fk;. 482. — Arteries of Distal Part of Right Hind 

 Limb of Pig, Anterior View. 

 a. Anterior tibial artery, continued on tarsus 

 as the dorsalis pedis; 6, perforating tarsal artery; 

 c, dorsal metatarsal arteries; d, common digital ar- 

 teries; e, proper digital arteries. 



Fig. 483. — Arteries of Distal Part of Right Hind 

 Limb of Pig, Posterior View. 

 /, Saphenous artery, continued as internal 

 tarsal artery; g, external tarsal artery; h, internal 

 plantar artery; h' , external plantar artery; i, per- 

 forating tarsal artery; j, deep plantar metatarsal 

 arteries; k, common digital artery; /, proper digital 

 arteries. 



the corresponding interosseous spaces and unite with branches of the volar meta- 

 carpals to form three common digital arteries. Each of these divides into two 

 proper digital arteries, which descc^id along the interdigital surfaces of the digits. 

 (Jn the volar surfact; are two volar arches, superficial and deep, from which three 

 superficial and three deep volar metacarpal arteries arise. The deep arteries 

 unite near the distal end of the space between tli(> i)rincipal metacarpal bones to 

 form a stem which unites with the middle (third) superficial artery. The superficial 

 arteries unite to form an arch from which proper digital arteries are given off to the 

 axial aspect of the small digits, and a common digital which supplies two volar 

 proper digital arteries to each of the chief digits. 



