412 THE PEOCEEDINGS OF THE LINNEAN SOCIETY 



further down the arm, a strong cutaneous brancli (external 

 cutaneous of musculo-spiraV) for the supply of the anterior alar 

 fold, reaches the forearm and gives a muscular branch to the 

 extensor carpi radialis longior and extensor raetacarpi radialis.* 

 It then divides into three branches ; of these that situated nearest 

 the radial side courses to the hand in contact with the extensor 

 longus poUicis and extensor indicis, gives off a branch to the 

 interossei muscles, one to the extensor brevis pollicis and one to 

 the adductor manus, and ends in cutaneous nerves for the supply 

 of the dorsal surface of the three digits. The middle division gives 

 a twig to the anconeus, and ends in two branches, one of which 

 supplies the extensor commumis digitorum, and the other goes to 

 supply the skin on the ulnar side of the manus ; the last, or most 

 ulnar, of the three divisions divides into two branches — one 

 supplying the extensor carpi ulnaris, and the other the skin on 

 the ulnar border of the forearm. 



The anterior brachial nerve, after giving a branch to the biceps, 

 and a cutaneous twig to the skin covering the upper part of the 

 arm, runs down the inner surface of the arm to the hollow in 

 front of the elbow-joint, near which it gives off a cutaneous 

 nerve (external cutaneous of musculo-cutaneous) to the skin of the 

 radial side of the forearm, and a muscular branch to the brachialis 

 anticus muscle ; it then divides into two trunks. The first of 

 these, passing to the radial border of the forearm, gives off two 

 small cutaneous twigs, and a branch which supplies the flexor 

 muscle carpi ulnaris, and divides into two branches, one of which 

 runs along the ulnar border of the flexor carpi ulnaris to the 

 hand, where it supplies the adductor manus and becomes cuta- 

 neous on the third digit ; while the other passes under the flexor 

 carpi ulnaris to the deep surface of the flexor sublimis degitorum, 

 the tendon of which it accompanies to the hand, where it ends in 

 two small superficial branches. 



The second of the two main trunks of the anterior brachial 

 (media7i) divides into three branches ; one of these supplies the 

 pronator muscles ; another passes under the pronators and 

 supplies the flexor profundus digitorum ; while the third and 



* Extensor metacarpi longus, of Tiedemann ; abductor pollicis longus, of RUding^er. 



