356 A MANUAL OF ANATOMY 



(2) to flex their metacarpo-phalangeal joints ; (3) to flex the wrist- 

 joint ; and (4) to assist in flexion of the elbow- joint. 



Radial Artery. — ^The radial artery is one of the terminal branches 

 of the brachial, from which it arises in the anticubital space, opposite 

 the upper part of the neck of the radius. It is smaller than the ulnar, 

 which is the other terminal branch, and in point of direction the 

 vessel is the continuation of the brachial. Its destination is the 

 palm, to reach which it passes at first downwards and slightly 

 outwards, as low as the styloid process of the radius. Here the 

 vessel passes to the back of the wrist beneath the styloid process 

 and upon the external lateral ligament, after which it sinks between 

 the two heads of the abductor indicis muscle. In this way it 

 reaches the palm, where it anastomoses with the profunda branch 

 of the ulnar artery, and so forms the deep palmar arch. The vessel 

 is divided into three parts. The first part lies in front of the fore- 

 arm, the second on the back of the wrist, and the third in the palm. 



First Part. — This part extends from the origin to the styloid pro- 

 cess of the radius. Its direction is downwards and slightly outwards, 

 and its course may be indicated by a line drawn from a point just 

 below the bend of the elbow, midway between the epicondyles 

 of the humerus, to a point about | inch internal to the styloid process 

 of the radius. In the upper third the vessel lies between the 

 brachio-radialis externally and pronator radii teres internally, 

 being overlapped by the fleshy belly of the former. Thereafter it 

 is placed between the brachio-radialis externally and flexor carpi 

 radialis internally, and in the lower half of the forearm, where 

 these muscles are replaced by their tendons, the vessel is quite 

 superficial. 



Relations — Superficial. — ^The integument, and margin of the 

 brachio-radialis in the upper third, or more. Branches of the 

 musculo-cutaneous nerve are distributed over the line of the vessel. 

 Deep. — From above downwards it lies upon (i) the tendon of inser- \ 

 tion of the biceps ; (2) the supinator radii brevis ; (3) the tendon of i 

 insertion of the pronator radii teres ; (4) the radial origin of the flexor j 

 sublimis digitorum ; (5) the flexor longus poUicis ; (6) the pronator 

 quadratus ; and (7) the lower end of the radius. External. — The \ 

 brachio-radialis throughout the whole of the forearm, and the I 

 external vena comes. The radial nerve in the upper part lies a little (1 

 to the outer side of the vessel ; at the centre it is closer to it ; and in | 

 the lower part the nerve leaves the artery by turning backwards i*: 

 beneath the tendon of the brachio-radialis. Internal. — The in-[j 

 ternal vena comes, pronator radii teres in the upper third, and 5 

 thereafter the flexor carpi radialis. H 



Branches of the First Part. — The first part gives off the following i 

 branches, namely, radial recurrent, muscular, anterior radial If, 

 carpal, and superficial volar. 



The radial recurrent artery, usually of large size, arises from the I 

 outer side of the radial close to its commencement, and passes out-lji 

 wards beneath the brachio-radialis, where it rests on the supinator'i 



i 



