648 THE VASCULAR SYSTEMS 



' the deep branch of the ulnar nerve. The branches of the deep palmar arch are the 

 palmar interosseous, perforating and palmar recurrent vessels (page 650). 



Peculiarities. The origin of the radial artery, according to Quain, is, in nearly one case in 

 eight, higher than usual; more frequently arising from the axillary or upper part of the brachial 

 than from the lower part of this vessel. The variations in the position of this vessel in the arm 

 and at the bend of the elbow have been already mentioned. In the forearm it deviates less fre- 

 quently from its position than the ulnar. It has been found lying over the fascia instead of 

 beneath it. It has also been observed superficial to the Brachioradialis, instead of under its 

 inner border; and in turning around the wrist it has been seen lying over, instead of beneath, 

 the Extensor tendons of the thumb. 



Surface Marking. The position of the radial artery in the forearm is represented by a line 

 drawn from the outer border of the tendon of the Biceps in the centre of the hollow in front 

 of the elbow-joint with a straight course to the inner side of the forepart of the styloid process 

 of the radius. 



Applied Anatomy. The radial artery is much exposed to injury in its lower third, and is 

 frequently wounded when the hand has been driven through a pane of glass, by the slipping of a 

 knife or chisel held in the other hand, and similar accidents. The injury is often followed by 

 a traumatic aneurism, for which the operation of extirpation or laying open the sac after securing 

 the vessel above and below is required. 



The operation of tying the radial artery is required in cases of wounds either of its trunk or 

 of some of its branches, or for aneurism; and it will be observed that the vessel may be exposed 

 in any part of its course through the forearm without the division of any muscle fibres. The 

 operation in the middle or inferior third of the forearm is easily performed, but in the upper 

 third, near the elbow, it is attended with some difficulty, from the greater depth of the vessel 

 and from its being overlapped by the Brachioradialis muscle. 



To tie the artery in the upper third an incision three inches in length should be made through 

 the integument, in a line drawn from the centre of the bend of the elbow to the front of the styloid 

 process of the radius, avoiding the branches of the median vein; the fascia of the arm being 

 divided and the Brachioradialis drawn a little outward, the artery will be exposed. The venae 

 comites should be carefully separated from the vessel, and the ligature passed from the radial to 

 the ulnar side. 



In the middle third of the forearm the artery may be exposed by making an incision of similar 

 length on the inner margin of the Brachioradialis. In this situation the radial nerve lies in 

 close relation with the outer side of the artery, and should, as well as the veins, be carefully 

 avoided. 



In the lower third the artery is easily secured by dividing the integument and fascia in the 

 interval between the tendons of the Brachioradialis and Flexor carpi radialis muscles. 



Branches (Figs. 462 and 464). The branches of the radial artery may be 

 divided into three groups, corresponding with the three regions in which the vessel 

 is situated. 



C Radial recurrent. C Posterior radial carpal. 



In the J Muscular. At the 1 First dorsal interosseous. 



Forearm j Anterior radial carpal. Wrist ] Dorsales pollicis. 

 L Superficial volae. t Dorsalis indicis. 



C Princeps pollicis. 

 Radialis indicis. 

 In the Hand ^ Perforating. 



Palmar interosseous. 

 . Palmar recurrent. 



The radial recurrent (a. recurrent radialis} (Fig. 464) is given off imme- 

 diately below the elbow. It ascends between the branches of the musculospiral 

 nerve lying on the Supinator [brevis], and then between the Brachioradialis and 

 Brachialis anticus, supplying these muscles and the elbow-joint, and anastomosing 

 with the anterior terminal branch of the superior profunda. 



The muscular branches (rami musculares) are distributed to the muscles on 

 the radial side of the forearm. 



