DEEP VEINS OF UPPER EXTREMITY 643 



II. THE DEEP VEINS OF THE UPPER EXTREMITY 



The deep veins of the upper extremity accompany their corresponding 

 arteries and consequently require no detailed description. There are two veins to 

 each artery l^elow the level of the axilla, known as the companion veins or vena? 

 comites. In the leg, as will be afterwards noticed, the vena3 comites of the main 

 arteries extend as far as the knee only. The deep veins all contain numerous 

 valves, and connnunicate at frequent intervals througli intermuscular veins with the 

 superficial. 



Beginning at the fingers, two minute veins accompany each digital artery 

 along the sides of the fingers, and, uniting at the cleft, form interdigital veins 

 which join the venae comites of the arteries, forming the superficial palmar arch. 

 In like manner the veins accompanying the arteries forming the deep arch receive 

 tributaries corresponding to the branches of that arch. The venae comites from 

 the ulnar side of the superficial and deep arches unite at the spot where the ulnar 

 artery divides into the superficial and deep branch to form two ulnar venae comites; 

 whilst those on the radial side of the superficial and deep arch accompany the su]ier- 

 ficial volar artery and the termination of the radial artery respectively, and unite 

 at the spot where the superficial volar is given off from the radial artery, to form the 

 radial yenas comites. The ulnar and radial venae comites thus formed course up 

 the forearm with their respective arteries, receiving numerous tributaries from the 

 muscles amongst which they run, and giving frequent communications to the super- 

 ficial veins. They finally unite at the bend of the elbow to form the brachial venae 

 comites. The ulnar venae comites receive, before joining the radial, the companion 

 veins of the interosseous arteries. At the bend of the ell)ow the deep veins are 

 connected with the superficial median vein by a short, thick trunk, the deep median 

 vein. 



The brachial venae comites accompany the brachial artery, the inner vein 

 receiving at the lower border of either the teres major or su1;)sca})ularis muscle the 

 outer vein and the basilic vein, to form a single axillary vein. 



The venae comites of the arteries of the arm anastomose with one another by 

 frequent cross branches. 



The axillary vein is formed by the junction of the inner brachial vena comes 

 with the ])asilic vein at the lower border of either the teres major or sul)scapularis 

 muscle. It is a vessel of large size, conveying as it does nearly the whole of the 

 returned blood from the upper extremity. It accompanies the axillary artery 

 through the axilla, lying to its inner side and at the upper part of the space on a 

 sliglitly lower i)lane. At the outer l)order of the first ril) it changes its name to the 

 subclavian. It has one or two axillary glands in close connection with it, and is 

 lial)le, if care is not taken, to be wounded in removing these glands when infiltrated 

 with cancer secondary to cancer of the breast. The vein contains a pair of valves, 

 usually placed near the lower border of the subscapularis muscle. It receives in its 

 course through the axilla: — (1) The subscapular veins which accompany the sub- 

 scapular artery; (2) the circumflex veins accompan3''ing the circumflex arteries; 

 (3) the long thoracic veins accompanying the long thoracic artery; (4) numerous 

 small veins returning the l)lood from the axillary glands; (5) the_ veins correspond- 

 ing to the branches of the thoracic axis; and (B) the cei^halic vein. 



The subclavian vein (fig. 329) is the continuation of the axillary. It begins 

 at the outer l)order of the first rib, and terminates by joining the internal jugular to 

 form the innominate vein opposite the outer part of the sterno-clavicular articula- 

 tion. It lies anterior to the subclavian artery and on a lower plane, and is se})arated 

 from the artery in the second part of its course by the scalenus anticus muscle. The 

 subclavian vein, just before the spot where it is joined l\v the external jugular, 

 contahis a pair of valves. 



Tributaries. — Near the outer border of the sterno-mastoid nmsele it receives 

 the external jugular vein. Occasionally the cephalic vein, (^r a branch from the 

 cephaHc (the jugulo-cei)halic), passes over the clavicle to the subclavian (fig. 390). 



Chief variations.— (1) Tlie subclavian vein may niii on a higher plane than usual, lying 



