734 THE VASCULAR SYSI^EMS 



between the Pectoralis major and Deltoid muscles, lying in the same groove 

 with the descending or humeral branch of the acromiothoracic artery. It pierces 

 the costocoracoid membrane, and, crossing the axillary artery, terminates in the 

 axillary vein just below the clavicle. This vein is occasionally connected with 

 the external jugular or subclavian by a branch which passes from it upward in 

 front of the clavicle. 



The accessory cephalic vein (v. cephalica accessoria) arises either from a small 

 tributary plexus on the back of the forearm or from the ulnar side of the dorsal 

 venous arch; it joins the cephalic below the elbow. In some cases the accessory 

 cephalic springs from the cephalic above the wrist and joins it again higher up. 

 A large oblique branch frequently connects the basilic and cephalic veins on the 

 back of the forearm. 1 



The Deep Veins of the Upper Extremity. 



The deep veins of the upper extremity (Fig. 511) follow the course of the 

 arteries, forming their venae comites, or companion veins. Usually there is one 

 vein lying on each side of the corresponding artery, and they are connected at 

 intervals by short transverse branches. 



Two digital veins accompany each artery along the sides of the fingers; these, 

 uniting at their base, pass along the interosseous spaces in the palm, and terminate 

 in the two venae comites which accompany the superficial palmar arch. Branches 

 from these vessels on the radial side of the hand accompany the superficialis 

 volae, and on the ulnar side terminate in the deep ulnar veins (Fig. 511). The 

 deep ulnar veins, as they pass in front of the wrist, communicate with the inter- 

 osseous and superficial veins, and at the elbow unite with the deep radial veins 

 to form the venae comites of the brachial artery. The venae comites of the brachial 

 communicate by numerous transverse branches, which cross over or under the 

 artery. 



The interosseous veins (Fig. 511) accompany the anterior and posterior 

 interosseous arteries. The anterior interosseous veins commence in front of the 

 wrist, where they communicate with the deep radial and ulnar veins; at the upper 

 part of the forearm they receive the posterior interosseous veins, and terminate in 

 the venae comites of the ulnar artery. 



The deep palmar veins accompany the deep palmar arch, being formed by 

 tributaries which accompany the ramifications of that vessel. At the wrist they 

 receive a dorsal and a palmar tributary from the thumb. The deep palmar veins 

 communicate with the deep ulnar veins at the inner side of the hand, and on the 

 outer side terminate in the deep radial veins (Fig. 51 1), which are the venae comites 

 of the radial artery. Accompanying the radial artery the deep radial veins ter- 

 minate in the venae comites of the brachial artery. 



The brachial veins (vv. brachiales} (Fig. 511) are placed one on each side of 

 the brachial artery; receiving tributaries corresponding with the branches given 

 off from that vessel; at the lower margin of the Subscapularis muscle they join the 

 axillary vein. 



These deep veins have numerous anastomoses, not only with each other, but 

 also with the superficial veins. One of the brachial veins empties into the axillary, 

 the other, usually the smaller, generally unites with the basilic. 



The axillary vein (v. axillaris} (Fig. 512) is of large size, and is the continuation 

 upward of the basilic vein. It commences at the lower border of the tendon of the 

 Teres major muscle, increases in size as it ascends, by receiving tributaries corre- 



1 Concerning the variations in the arrangement and course of the veins of the upper extremity, consult the 

 article by W. Krause in Henle's Handbuch der Anatomic. 



