THE FOREARM. 



flexors and pronator radii teres; the mass of muscles on the outer side between it 

 and the radius posteriorly are the extensors, supinator (brevis), and brachioradialis. 

 The inner edge of the brachioradialis is indicated by a line drawn from the outer 

 side of the biceps tendon to the outer surface of the styloid process of the radius. 

 A line from the medial (internal) condyle running obliquely across the forearm to 

 the middle of the radius indicates the pronator radii teres muscle. A line from the 

 medial condyle to the middle of the wrist indicates the palmaris longus muscle; 

 it is sometimes absent. Another line from the same point above to a centimetre 

 to the radial side of the palmaris' longus tendon at the wrist indicates the flexor 



Triceps tendon 



Internal condyle 

 Olecranon process 



Ulna 



Extensor carpi ulnaris 



Styloid process of ulna 



Brachialis anticus 

 External bicipital furrow 



Depression, head of radius 



External condyle 



Brachioradialis and extensor 

 carpi radialis longior 

 Anconeus 



Extensor communis digitorum 



Extensors of the thumb 



Styloid process of radius 

 Extensor longus pollicis 



FIG. 328. Surface anatomy of the back of the forearm. 



carpi radialis muscle. The tendons of both these muscles can readily be seen. A 

 line drawn from the medial (internal) condyle to the pisiform bone at the wrist 

 indicates the anterior edge of the flexor carpi ulnaris muscle. 



Having located the superficial muscles the arteries and nerves can be traced. 

 The brachial artery bifurcates about a finger's breadth below the bend of the elbow. 

 A line drawn from the inner edge of the biceps tendon, or a point midway between 

 the two condyles, to the anterior surface of the styloid process of the radius indi- 

 cates the course of the radial artery. In the upper half of the forearm it is over- 

 lapped by the edge of the brachioradialis. In the lower half it is uncovered by 

 muscle and lies in the groove formed by the brachioradialis on the outer side and the 

 flexor carpi radialis on the inner. The ulnar artery describes a marked curve toward 

 the ulnar side until it reaches the middle of the forearm, when it passes down in a 

 straight line from the medial (internal) condyle to the radial side of the pisiform bone. 



