THE VESSELS. 317 



triceps, perforates the lig. intermusc. intern, (with n. cubital.), and reaches as 

 far as the articulation, where it supplies the triceps and brachial. intern. 



3. Collateralis ulnaris inferior [s. anastomodica] , arises above the elbow, 

 passes obliquely downwards and inwards, towards condyl. hum. intern., and is 

 lost in rete articulare cubiti, m. brachialis and pronator teres. 



The brachial artery bifurcates commonly (half an inch) below, 

 sometimes in, frequently also above the flexure of the arm into art. 

 radialis and ulnaris (at the inferior or superior third of the upper 

 arm, indeed, even in the axillary cavity. . Cruveilhier.) 



567. I. Radialis, the radial artery, 



the external, smaller, and more superficial branch of art. brachialis, 

 passes directly downwards, and rather obliquely outwards, along 

 the internal border of the radius, as far as the articulation of the 

 hand, turns round the proc. styloid radii and os naviculare upon 

 the dorsal surface of the carpus, and immediately again between 

 the first and second metacarpal bones forwards into the hollow of 

 the hand, and forms the arcus volaris profundus. Situation : 



a. From the commencement to the carpus : behind the internal 

 border of m. supinator longus, below covered only by the fascia 

 and skin ; upon m. supinator brevis, pronator teres, flex, digit, 

 sublim., long, pollic., pronat. quadrat., then close upon the bone 

 on the inner side of the tendon of m. supinator longus and the n. 

 radialis. 



b. On the carpus : covered obliquely by the tendons of abductor 

 pollic. long., flex, long., and brevis, close upon the bones. 



c. In the hollow of the hand (see arcus volaris profundus.) 

 Variety. It frequently inclines to the back of the fore-arm at a 



point higher up (two or three inches above the carpus?) 



Besides many (forty) muscular branches and a transversa carpi 

 volaris to the rete carpeum volare, the radial artery yet gives off the 

 following branches : 



1. Recurrens radialis. Origin: behind, close to the commencement of 

 art. radialis (also from the brachialis). Course : runs outwards and up- 

 wards to condylus externus. Situation : between supinat. long, and brevis 

 (above brachialis intern.). Anastomoses with profunda humeri. Branches : 

 from the convexity downwards and outwards to mm. supinatores and ra- 

 diales extern.; to the rete articulare cubiti. 



2. Samus volaris superficialis, s. radio-palmaris. Or. : above os naviculare 

 from the inner side of art. radialis. Course : passes over the origin of a6- 

 ductor pollic. brevis, on the external border under aponeurosis palmaris to 

 the arcus volar. sublimis. Branches to the muscles of the thumb, or even 

 to the outer side of the middle and the two sides of the index fingers. 



