568 



THE AETERIES. 



Fig. 283. 



1. First Terminal Branch of the Posterior Hadial Artery, 

 or Common Trunk of the Interosseous Metacarpal 

 Arteries. 1 (Fig. 283, 5.) 



This arterial branch separates at a very acute anglo 

 from the collateral artery of the cannon. It descends 

 inside and behind the carpus, accompanied by the prin- 

 cipal subcutaneous vein of the limb, and with it is 

 included underneath a superficial fascia, which maintains 

 them in a channel hollowed on the external face of the 

 carpal fibrous sheath. It thus arrives within the head of 

 the inner metacarpal bone, where it is inflected to the 

 outer side by crossing the superior extremity of the sus- 

 pensory ligament, and between it and the metacarpal liga- 

 ment the latter furnishes to the perforans tendon ; it anas- 

 tomoses by inosculation with a descending branch which 

 emanates from the superficial arch that, above the carpus, 

 unites the epicondyloid or ulnar artery to the origin 

 of the collateral artery of the cannon (Fig. 283, 6). The 

 loop-like anastomosis thus formed by the radio-palmar 

 artery, exactly corresponds to the deep palmar arch of 

 pentadactylous animals, particularly to that of Man. We 

 propose to name it also the subcarpal arch, by reason of 

 the position it occupies in regard to the carpus, reser- 

 ving the appellation of supracarpal arch for the super- 

 ficial palmar arch, which is represented by the anastomosis 

 established between the collateral artery of the cannon 

 and the epicondyloid artery. 



Four principal branches emanate from this subcarpal 

 arch : these are the metacarpal interosseous arteries, dis- 

 tinguished into' posterior or palmar, and anterior or dorsal. 



a. The posterior interosseous arise, one on the right, 

 the other on the left, at the head of the lateral meta- 

 carpal bones, each descending on its own side, and in a 

 flexuous manner, along these rudimentary bones, in the 

 angular groove formed by their inner face and the pos- 

 terior face of the principal metacarpal bone, terminating 



The muscles and tendons have been removed, only a small portion of 

 the perforaus tendon being left ; the os pedis has been chiselled 

 away on its plantar face to expose the semilunar anastomosis. 

 1, Posterior radial artery ; 2, Innominate carpal branch ; 3, Supra-* 

 carpal arch ; 4, Epicondyloid (ulnar) artery ; 5, Radio-palmar 

 artery, or common trunk of the interosseous metacarpal arteries ; 

 6, Subcarpal arch ; 7, 7, Posterior interosseous metacarpal arteries ; 

 7', 7', Anterior interosseous metacarpal arteries; 8, 8, Their origin; 



ARTERIES OF THE 9, Collateral artery of the cannon ; 10, Its communicating branch 

 FORE-FOOT, SEEN with the interosseous arteries ; 11, 11, Digital arteries, 12, Semi- 

 FROM BEHIND. lunar anastomosis in the os pedis ; 13, Emergent branches of this 



anastomosis ; 14, Plantar ungueal artery, forming this anastomotic 



arch ; 15, Origin of the preplantar ungueal artery ; 16, Origin of the plantar-cushion 

 artery ; 17, Origin of the anterior branch of the coronary circle ; 18, Posterior branch of 

 the same. 



1 This vessel corresponds to the radio-palmar artery of Man, by which name it is 

 sometimes designated. Bigot has improperly named it the deep plantar artery. 



