THE BRACniAL OR AXILLARY ARTERIES. 



'I'll. Be terminal minuscules of the anterior radial artery arc distributed 

 t<> the carpal articulation, or the sheaths of the extensor tendons, and com- 

 innniciitu \\ith the dorsal interosseous metacarpal arteries. 



The collateral branches given off by this artery are very numerous, the 

 majority of them being detached from the suj>crior jxjrtion of the vessel 

 mar the elbow ; they are intended to supply that articulation, but more 

 especially the muscular masses lying in its neighbourhood, or covering it. 



Such is the usual disposition of the anterior radial artery ; though it in 

 liable to numerous variations: principally in the manner in which it comports 

 itsdf with the iuterosseous artery of the fore-arm, which may even supple- 

 ment it for the whole of the middle and lower part of its course. This will 

 be noted in describing the next artery. 



2. Posterior Radial Artery. (Figs. 283, 1 ; 347, B.) 



This vessel, in its volume and direction, represents the continuation of 

 the humeral artery. It descends, along with the ulno-plantar nerve, on the 

 internal ligament of the humero-radial articulation, behind the terminal 

 inity of the coraco-radialis ; then under the internal flexor of the meta- 

 carpus, its satellite muscle. Arriving at the inferior extremity of the radius, 

 it divides into two terminal branches ; which are, the common trunk of the 



..wuin metacarpal arteries and the collateral artery of the cannon. 

 The following are the principal collateral branches furnished by the 

 rior radial artery : 



1. At the superior extremity of the radius, articular ramuscules which 

 anastomose with analogous branches from the epicondyloid artery. 



2. A little lower, large divisions destined for the muscles of the posterior 

 antibrachial region, some of them arising from the next artery. 



3. The interosseous artery of the fore-arm, a considerable vessel which 

 originates at the same point as the preceding the radio-uluar arch, and 

 which crosses this from within to without, after traversing the posterior face 

 of tin radius, beneath the perforans muscle, to descend along the lateral 



sor muscle of the phalanges, in the channel formed outwardly by the 

 union of the two hones of the fore-arm. This interosseous artery furnishes, 

 immediately after its exit from the radio-ulnar arch, several branches to the 

 articulation of the ell>ow and the antibrachial muscles. At its terminal 



uiity it usually divides into a number of branches, the majority of 

 which join the branches sent to the carpus by the anterior radial artery. It 



i that it does show some fine anastomoses with one; of the divisions of 

 the latter artery in front of, or outside the articulation of the elbow ; some- 

 it ilirectly joins that vessel ; and I have seen it. on tin contrary, receive 

 the anterior r.idial artery, which it in part supplanted. 



4. Several muscular and nnisculo-cutaneous ramuscules without any li 

 arrangement, arising from different points of the course of the parent artery, 



. the preceding divisions. 



5. A .i p branch, also liable to very numerous variations, having its 

 origin at the radial in< rtioii of the perfomtus muscle, descending on the 



: ior face of the ratlins, chiefly destined to the carpus, and remarkable 

 for the anastomoses that its internal divisions contract with the anterior 



i art.rv. and for those which occasionally unite its external ramifications 

 to the ultimate branches of the interosseous artery of the fore-arm or the 



..dyluid artery (Fig. 283, 2). 



