608 THE BLOOD- VASCULAR SYSTEM. 



The Median Basilic Vein passes obliquely inward, in the groove between the 

 Biceps and Pronator radii teres, and joins the common ulnar to form the basilic. 

 This vein passes in front of the brachial artery, from which it is separated by a 

 fibrous expansion (the bicipital fascia) which is given off from the tendon of che 

 Biceps to the fascia covering the Flexor muscles of the forearm. Filaments of 

 the internal cutaneous nerve pass in front as well as behind this vessel. 1 



Venesection is usually performed at the bend of the elbow, and as a matter of practice the 

 largest vein in this situation is commonly selected. This is usually the median basilic, and there 

 are anatomical advantages and disadvantages in selecting this vein. The advantages are, that 

 in addition to its being the largest, and therefore yielding a greater supply of blood, it is the 

 least movable and can be easily steadied on the bicipital fascia on which it rests. The disadvan- 

 tages are, that it is in close relationship with the brachial artery, separated only by the bicipital 

 fascia ; and formerly, when venesection was frequently practised, arterio-venous aneurism was 

 no uncommon result of this practice. Another disadvantage is, that tbe median basilic is 

 crossed by some of the brandies of the internal cutaneous nerve, and these may be divided in 

 the operation, giving rise to " traumatic neuralgia of extreme intensity " (Tillaux). 



The Basilic Vein is of considerable size, formed by the coalescence of the common 

 ulnar vein Avith the median basilic. It passes upward along the inner side of the 

 Biceps muscle, pierces the deep fascia a little below the middle of the arm, and, ascend- 

 ing in the course of the brachial artery to the lower border of the tendons of the Latis- 

 sirnus dorsi and Teres major muscles, it is continued onward as the axillary vein. 



The Cephalic Vein courses along the outer border of the Biceps muscle, lying 

 in the same groove with the upper external cutaneous branch of the musculo-spiral 

 nerve, to the upper third of the arm ; it then passes in the interval between the 

 Pectoralis major and Deltoid muscles, lying in the same groove with the descending 

 or humeral branch of the acromial-thoracic artery. It pierces the costo-coracoid 

 membrane, and crossing the axillary artery, it 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 Deep Veins of the Upper Extremity follow the course of the arteries, 

 forming their venae comites. They are generally two in number, one lying on 

 each side of the corresponding artery, and they are connected at intervals by 

 short transverse branches. 



There are two digital veins accompanying 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 accom- 

 pany the superficialis volae, and on the ulnar side terminate in the deep ulnar 

 veins. The deep ulnar veins, as they pass in front of the wrist, communicate with 

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

 veins to form the venae comites of the brachial artery. 



The Interosseous Veins 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. They communicate 

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

 terminate in the venae comites of the radial artery. At the wrist they receive a 

 dorsal and a palmar tributary from the thumb, and unite with the deep radial 

 veins. Accompanying the radial artery, these vessels terminate in the venae 

 comites of the brachial artery. 



1 Cruveilhier says: "Numerous varieties are observed in the disposition of the veins of the 

 elbow; sometimes the common median vein is wanting; but in those cases its two branches are fur- 

 nished by the radial vein, and the cephalic is almost always in a rudimentary condition. In other 

 cases only two veins are found at the bend of the elbow, the radial and ulnar, which are continuous, 

 without any demarcation, with the cephalic and basilic." 



