400 



THE ARTERIES OF THE UPPER LIMB. 



extends from the lower border of the posterior fold of the axilla, to 

 about a finger's breadth below the bend of the elbow, or to a point 

 opposite the neck of the radius, where it divides into the radial and 

 ulnar arteries. The vessel gradually inclines from the inner side to the 

 fore part of the limb, lying in the depression along the inner border of 

 the coraco-brachialis and biceps muscles ; and its direction may be 

 marked out by a line drawn from midway between the folds of the 

 axilla to the middle point between the condyles of the humerus. To 

 command the flow of blood through the artery at its upper part, pres- 

 sure should be directed outwards, while over the lower end of the vessel 

 the pressure should be made from before backwards. 



The brachial artery lies beneath the integument and fascia of the 

 arm as far as the bend of the elbow, where it sinks deeply in the in- 

 terval between the pronator teres and supinator longus muscles, and is 

 covered by the semilunar fascia, a fibrous expansion given from the 

 tendon of the biceps to the fascia of the forearm. It rests at first on 

 the long head of the triceps muscle, the nrasculo-spiral nerve, and the 

 superior profunda artery intervening ; it then inclines forwards over 

 the insertion of the coraco-brachialis muscle, and lies thence to its 

 termination on the brachialis anticus. At its outer side it is in appo- 

 sition first with the coraco-brachialis, and afterwards and for the greater 

 part of its length with the biceps, the inner border of one or both 

 muscles sometimes slightly overlapping it. 



Fig. 26i 



Fig. 262. — Superficial Dissection op the 

 Blood- Vessels and Nerves at the Bend of 

 THE Arm (from R. Quain). 



a, two branches of the internal cutaneous 

 nerve ; a' a", the descending twigs of the same 

 nerve ; i, placed over the biceps near its inser- 

 tion and close to the external cutaneous nerve ; 

 h', anterior twigs of the same nerve accompany- 

 ing the median vein ; 1, placed on the fascia of 

 the arm near the bend of the arm, above the 

 place where it has been opened to show the lower 

 part of the brachial artery with its vense comites, 

 of which one is entire, marked 2, and the other 

 has been divided ; +, is placed between the 

 artery and the median nerve ; 3, basilic vein ; 

 3', 3', ulnar veins ; 4, cephalic vein ; 4', radial 

 vein ; 5, 5, median vein ; 3', 5, median basilic 

 vein ; 4', 5, median cephalic vein. 



FeJation to Veins. — Vense comites 

 are in close contact with the brachial 

 artery, short transverse branches of 

 communication passing fi'om one to 

 another, so as at many points to encircle 

 it. Superficial to the aponeurosis, the 

 basilic vein is placed over or to the inner 

 side of the artery in the lower half or 

 more, or in the whole length of its 

 course, according the level at which 

 the vein dips down to join the vense 

 comites ; and at the bend of the elbow the median basilic vein crosses 

 over the artery, the aponeurotic insertion of the biceps lying between them. 



