VENOUS SYSTEM. 



1407 



hi the fore-arm by many cutaneous branches 

 from either side. Opposite the elbow joint 

 these tributaries have ended in one vessel of 

 considerable size, the cephalic vein, which, 

 being joined by a branch from the median 

 vein (median cephalic), ascends between the 

 biceps and supinator longus muscles, follows 

 the outer margin of the biceps, traverses the 

 interspace between the pectoralis major and 

 the deltoid, and ultimately having arrived in 

 the subclavicular triangle, bends over the 

 upper edge of the pectoralis minor, penetrates 

 the thin expansion of the "fascia clavicularis" 

 (ligawentum bicorne), and enters the axillary 

 vein immediately beneath the clavicle. In 

 some instances a branch is continued upwards 

 from the cephalic vein, which passes over the 

 clavicle and communicates with the external 

 jugular vein. 



The ulnar or internal superficial veins have 

 their origins from veins which ramify on the 

 clorsum of the hand and of the two inner 

 fingers, one of which from the little ringer has 

 been long known as the " vena salvalella ;" 

 others arise anteriorly from subcutaneous 

 veins on the front of the wrist. In the vici- 

 nity of the elbow both sets of branches unite 

 to form one principal trunk, the basilic vein, 

 which is reinforced almost at the moment of 

 its formation by the median basilic vein, a 

 branch of very considerable size from the 

 median. 



The basilic vein, now much enlarged, as- 

 cends along the inner margin of the biceps 

 muscle, parallel to the brachial artery, but 

 more superficially than that vessel, (for the 

 deep fascia intervenes,) until it arrives oppo- 

 site the centre of the arm, when it pierces 

 the brachial aponeurosis, and joins one or 

 other of the vents comites of the brachial 

 artery. In a few instances the vein ascends 

 as high as the axilla, and entering that space 

 joins the trunk of the axillary vein. The 

 superficial veins in the front of the upper part 

 of the fore-arm unite to form a short trunk 

 termed median vein, which by its lateral 

 branches connects the radial and ulnar super- 

 ficial veins ; near the bend of the elbow the 

 median vein receives a large communicating 

 branch from the venee comites of the brachial 

 artery, and terminates by dividing into two 

 very considerable veins, termed median basilic 

 and median cephalic veins respectively : the 

 latter passes obliquely upwards and outwards, 

 over the tendon of the biceps, and joins the 

 cephalic vein ; the former, which is the 

 largest, inclines inwards, and in its course to 

 join the basilic trunk passes across the bra- 

 chial artery, separated from it only by the 

 " semilunar fascia" of the biceps tendon. 



The deep veins of the upper extremity ac- 

 company the ramifications of the larger arteries 

 chiefly, which in the lower as well as in the 

 upper extremity, are invariably attended by 

 two veins, one on either side, hence called 

 vents comites; transverse branches at short 

 intervals maintain a free communication 

 between these vessels. 



The vents comites of the ulmar artery are de- 



rived from veins which correspond to the di- 

 gital arteries, and which form a superficial 

 palmar arch of veins, which at its outer ex- 

 tremity receives branches from the deep radial 

 veins, through which the venae comites of the 

 radial and ulnar arteries are brought into com- 

 munication with each other. The associate 

 veins of the interosseous artery unite with the 

 venas comites of the ulnar artery. 



The vents comites of the radial artery com- 

 mence from the palmar interosscal veins, which 

 form a deep palmar arch across the heads of 

 the metacarpal bones, and are joined by veins 

 from the muscles of the thumb, and by branches 

 of the superficial arch which follow the course 

 of the arteria superficialis volae. The vena; 

 comites of both the radial and ulnar arteries 

 receive numerous tributaries from the veins 

 of the adjacent muscles, and ultimately unite 

 to form the 



Satellite veins of the brachial arlery, 

 The brachial vena? comites are joined by 

 veins which correspond to the branches 

 of the brachial artery in the arm (superior 

 and inferior profunda and anastomotica 

 magna), and also by the basilic vein. At 

 the lower part of the axilla, these veins, by 

 their union, form the axillary vein. 



The axillary vein returns all the blood from 

 the upper limb : it is formed by the union of 

 the brachial venae comites (with one or other 

 of which, in the arm, the basilic vein is con- 

 tinuous), whilst the cephalic vein joins it near 

 its termination. Like its accompanying artery, 

 the axillary vein consists of three stages, and 

 its relations to surrounding parts are identical 

 with those of that vessel. The vein is placed 

 internal and anterior to the artery throughout 

 its entire course. When the arm is abducted, 

 the vein becomes inferior. 



In addition to the cephalic vein, the axil- 

 lary trunk receives numerous brandies which 

 correspond to those of the axillary artery, 

 viz., the circumflex and subscapular veins, the 

 alar, and the long, superior, and acromial 

 thoracic veins. 



The axillary is the last vein of the upper 

 extremity, as we approach the heart, in which 

 valves exist : at the lower edge of the first 

 rib it becomes continuous with the subcla- 

 vian vein. 



Subclavian vein. This great vessel extends 

 from the axillary vein to the inner margin of the 

 scalenus anticus muscle, where it unites __with 

 the internal jugular vein, to form the vena 

 innominata. The subclavian vein therefore 

 corresponds to the second and third stages 

 only of the subclavian artery ; and, as the 

 direction of the vein is nearly transverse, 

 whilst that of the artery describes an arch, it 

 necessarily follows that the former vessel is 

 much shorter than the latter. On both sides 

 of the neck the scalenus anticus muscle, and 

 the phrenic and pneumogastric nerves, are, 

 interposed between these associated vessels. 

 The subclavian vein is related anteriorly to 

 the subclavius and sterno-mastoid muscles, to 

 the clavicle, supra-scapular artery, platysma, 

 and superficial structures of the neck, and 



