RADIAL ARTERY AND BRANCHES. 265 



below that with the radial artery to which its tendon is taken as the guide. 

 The ulnar border is in contact at first with the palmaris longus muscle, 

 and for about two inches above the wrist, with the median nerve. 1 



Action. The hand being free the muscle flexes first the wrist joint, 

 inclining the hand somewhat to the radial side ; and will assist in bringing 

 forwards the lower end of the radius in pronation. Still continuing to 

 contract, it bends the elbow. 



The PALMARIS LONGUS (fig. 80, 5 ) is often absent : or it may present 

 great irregularity in the proportion between the fleshy and tendinous parts. 

 Its origin is connected, like that of the preceding muscle, to the common 

 tendon, the fascia, and the intermuscular septa. Its long thin tendon is 

 continued along the centre of the forearm ; and piercing the aponeurosis, 

 it passes over the annular ligament to end in the palmar fascia, and to join 

 by a tendinous slip the short muscles of the thumb. 



The palmaris is situate between the flexor carpi radialis and ulnaris, and 

 rests on the flexor sublimis digitorum. 



Action. Rendering tense the palmar fascia, the palmaris will afterwards 

 bend the wrist and elbow, like the other muscles of the superficial layer. 



The FLEXOR CARPI ULNARIS (fig 80, 7 ) has an aponeurotic origin from 

 the inner condyle of the humerus ; from the inner side of the olecranon ; 

 and from the ridge of the ulna between the internal and posterior surfaces 

 for three-fourths of the length. Most of the fibres are continued vertically 

 downwards, but others obliquely forwards to a tendon on the anterior part 

 of the muscle in the lower half, some joining it as low as the wrist ; and 

 the tendon is inserted into the pisiform bone, an offset being sent to the 

 muscles of the little finger. 



One surface of the muscle is in contact with the fascia ; and its tendon, 

 which can be felt readily through the skin, may be taken as the guide to 

 the ulnar artery. To its radial side are the palmaris and flexor digitorum 

 sublimis muscles. When the attachment to the inner condyle has been 

 divided, the muscle will be seen to conceal the flexor digitorum sublimis 

 and flexor profundus, the ulnar nerve, and the ulnar vessels ; between the 

 attachments to the condyle and the olecranon the ulnar nerve enters the 

 forearm. 



Action. The wrist is bent and the hand is drawn inwards by the con- 

 traction of the muscle. 



The RADIAL ARTERY (fig. 80, J ) is one of the vessels derived from the 

 bifurcation of the brachial trunk ; and its destination is the palm of the 

 hand. It is placed first along the outer side of the forearm as far as the 

 end of the radius ; next it winds backwards below the extremity of that 

 bone : and it enters finally the palm of the hand through the first inter- 

 osseous space. In consequence of this circuitous course the artery will be 

 found in three diti'erent dissections, viz., the front of the forearm, the back 

 of the wrist, and the palm of the hand. 



In the front of the forearm. In this part of the limb the position of the 

 artery will be marked, on the surface, by a line from the centre of the 

 hollow of the elbow to the fore part of the styloid process of the radius. 

 At first it lies on the inner side of the radius, but afterwards over that 

 bone. This vessel is smaller than the ulnar artery, though it appears in 

 direction to be the continuation of the brachial trunk ; and it is partly 



1 In the body of a woman which was well developed, the muscle was absent on 

 both sides. 



