316 APPLIED ANATOMY. 



The radial artery, though smaller than the ulnar, seems to be a direct con- 

 tinuation of the brachial because it proceeds in the same general direction while the 

 ulnar branches off to one side. It is divided into three parts according to the 

 region it traverses, viz., the forearm, the wrist, and the hand. It describes a slightly 

 outward curved line from a finger's breadth below the middle of the crease of the 

 elbow to a point on the front of the radius at the wrist, i cm. (-f in.) inside of its 

 styloid process. It is superficial in nearly its entire extent, being overlapped only 

 by the edge of the brachioradialis (supinator longus) in its upper third. This 

 muscle lies to its outer side all the way down to the styloid process. In the middle 

 third the cutaneous branch of the radial nerve lies close to the outer side of the 

 artery, but in the lower third the nerve leaves it to become subcutaneous, passing 

 . more toward the dorsum. 



To the inner side of the artery is the pronator radii teres muscle in its upper 

 third and the flexor carpi radialis for the rest of its course. At the wrist it rests on 

 the anterior surface of the radius, a centimetre to the inner side of its styloid process. 

 By compressing the vessel against the bone its pulsations can be readily felt, and here 

 is where the finger is applied in taking the pulse. 



The branches of the radial artery are the recurrent, muscular, anterior radial 

 carpal and superficial volar. 



The radial recurrent arises from the radial soon after its origin and follows the 

 radial nerve, in the groove between the brachialis anticus and brachioradialis. 



The anterior carpal is a small branch which joins with the corresponding branch 

 of the ulnar and anterior terminal branch of the anterior interosseous to form a so- 

 called anterior carpal arch which anastomoses with branches of the deep palmar arch 

 to supply the bones and joints of the carpus. 



The superficial volar leaves the radial artery just before it crosses the external 

 lateral ligament. It pierces the muscles of the thumb to anastomose with a superficial 

 branch of the superficial palmar arch. Sometimes this artery is so large that it can be 

 seen pulsating as it passes over the thenar eminence from the wrist downward. 



Ligation of the Ulnar Artery in the Forearm. The ulnar artery between 

 the elbow and wrist is so large that when wounded it may require ligation in any 

 part of its course. On account of the artery being deep beneath the flexor muscles 

 in the upper part of the forearm, the middle and lower portions are to be preferred 

 for ligation (Fig. 330). 



Ligation in the Upper Third. This is done only for wounds. The superficial 

 incision may be made in a line from the medial (internal) condyle to the middle 

 of the outer border of the radius. The fibres of the pronator radii teres are to 

 be parted, not cut, and the artery searched for crossing the wound almost at right 

 angles, on a line from the bifurcation of the brachial artery to the middle of the 

 inner border of the ulna. The artery is to be found lying between the superficial 

 flexor muscles arising from the medial condyle and the deep muscles arising 

 from the two bones and the interosseous membrane. It lies beneath the ulnar 

 head of the pronator radii teres, which separates it from the median nerve, which 

 is superficial to it and nearer the median line. 



Ligation in the Middle Third. The ulnar artery reaches the inner edge of 

 the ulna at its middle and from thence downward runs in a straight line from the 

 medial (internal) condyle to the radial side of the pisiform bone. It lies directly 

 under the deep fascia and along the radial or outer edge of the flexor carpi ulnaris 

 muscle, which can be made tense by extending and abducting the hand. 



In the upper part of its middle third the artery lies under the edge of the flexor 

 sublimis digitorum and the ulnar nerve lies a short distance to its ulnar side. In the 

 lower part of the middle third the artery and nerve lie close together, the nerve 

 being next to the tendon of the flexor carpi ulnaris. The tendon to the radial side 

 of the artery is one of the slips of the flexor sublimis digitorum. 



If difficulty is found in recognizing the edge of the flexor carpi ulnaris after the 

 skin incision has been made the hand should be extended and abducted: this may 

 make the muscle tense. Sometimes the intermuscular space is marked by a white 

 or yellow (fatty) line or by some small blood-vessels coming to the surface at this 

 point. The edge of the flexor carpi ulnaris is more likely to be to the radial than to 



