The Forearm. 77 



too, does the median nerve, which, passing down the 

 forearm between the two heads of the pronator radii 

 teres, crosses, and is separated from the ulnar artery by 

 the deep head of this muscle. On the outer side of the 

 vessel is the flexor sublimis digitorum, and, on the inner 

 side, are the flexor carpi ulnaris muscle and the ulnar 

 nerve. Both radial and ulnar arteries supply the forearm 

 by means of muscular, recurrent and interosseous branches, 

 the latter constituting the main blood supply of the 

 posterior surface. 



The nerves of the forearm are the median, the ulnar, 

 the radial, and the posterior interosseous. The median 

 nerve continues its direction downwards in a straight line 

 from the landmark spoken of above, viz., a point one- 

 half inch internal to the biceps tendon at the centre of 

 the bend of the elbow. It passes to the middle of the 

 front of the wrist below, and lies, at first, on the brach- 

 ialis anticus, then between the heads of the pronator radii 

 teres, and, lastly, on the flexor profundus muscle. This 

 nerve is separated from the ulnar artery by the deep head 

 of the pronator radii teres, and the order of these struc- 

 tures, from before backwards, at the point where the nerve 

 crosses the artery, is nerve, muscle and artery. At the 

 lowest part of the forearm the median nerve lies 

 behind the palmaris longus tendon, between the flexor 

 carpi radialis externally, and the flexor sublimis 

 digitorum internally. It supplies, in the forearm, all the 

 muscles of the anterior surface, excepting one and a half 

 muscles, viz., the flexor carpi ulnaris and the inner half 

 of the flexor profundus. The ulnar nerve enters the 

 forearm behind the internal condyle and supplies one 

 and a half muscles, viz., the flexor carpi ulnaris and the 

 inner half of the flexor profundus. As it descends in the 

 forearm it lies on the flexor profundus, has the flexor carpi 



