RADIAL. 411 



third of its course, it lies between the Supinator longus and the Pronator radii 

 teres ; in its lower two-thirds, between the tendons of the Supinator longus and 

 the Flexor carpi radialis. The radial nerve lies along the outer side of the artery, 

 in the middle third of its course ; and some filaments of the musculo-cutaneous 

 nerve, after piercing the deep fascia, run along the lower part of the artery as it 

 winds round the wrist. The vessel is accompanied by venso comites throughout 

 its whole course. 



PLAN OF THE KELATIONS OF THE EADIAL AETERY IN THE FOKEARM. 



In front. 



Integument, superficial and deep fasciae. 

 Supinator longus. 



Inner side. / ~~\ Outer side. 



Pronator radii teres. [ \^ Supinator longus. 



Flexor carpi radialis. [ ArtervNu \ Badial nerve (middle 



third). 



Behind. 



Tendon of Biceps. 

 Supinator brevis. 

 Pronator radii teres. 

 Flexor sublimis digitorum. 

 Flexor longus pollicis. 

 Pronator quadratus. 

 Radius. 



At the wrist, as it winds round the outer side of the carpus, from the styloid 

 process to the first interosseous space, it lies upon the external lateral ligament, 

 being covered by the Extensor tendons of the thumb, subcutaneous veins, some 

 filaments of the radial nerve, and the integument. It is accompanied by two 

 veins, and a filament of the musculo-cutaneous nerve. 



In the hand, it passes from the upper end of the first interosseous space, between 

 the heads of the Abductor indicis, transversely across the palm, to the base of 

 the metacarpal bone of the little finger, where it inosculates with the communL 

 eating branch from the ulnar artery, forming the deep palmar arch. It lies upon 

 the carpal extremities of the metacarpal bones and the Interossei muscles, being 

 covered by the Flexor tendons of the fingers, the Lumbricales, the muscles of the 

 little finger, and the Flexor brevis pollicis, and is accompanied by the deep branch 

 of the ulnar nerve. 



Peculiarities. The origin of the radial artery varies nearly in the proportion of one case in 

 eight. In one case the origin was lower than usual; in the others, the upper part of the 

 brachial was a more frequent source of origin than the axillary. 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 frequently from its position than the ulnar. It has been found 

 lying over the fascia, instead of beneath it. It has also been observed on the surface of the 

 Supinator longus, instead of along its inner border ; and in turning round the wrist, it has been 

 seen lying over, instead of beneath, the Extensor tendons. 



Surgical Anatomy. 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 easily exposed in any part of its course through the forearm. The operation in 

 the middle or inferior third of this region is easily performed ; but in the upper third, near the 

 elbow, the operation is attended with some difficulty, from the greater depth of the vessel, and 

 from its being overlapped by the Supinator longus and Pronator radii teres muscles. 



To tie the artery in this situation, an incision three inches in length should be made through 

 the integument, from the bend of the elbow obliquely downwards and outwards, on the radial 

 side of the forearm, avoiding the branches of the median vein ; the fascia of the arm being 



