MUSCLES ON THE DOKSAL SUKFACE OF THE FOKEAKM. .399 



Nerve-Supply. The supinator is supplied by a branch from the deep branch of the radial 

 nerve, which arises from the nerve before the main trunk enters the muscle (C. 5. 6.). 



Action. The muscle is an ex-tensor of the elbow, and the main supinator of the forearm. 

 In the latter action it is assisted by the biceps. 



RICEPS 



IACHII evr-r- 

 ENDON I 



VCHIO- 

 DIALIS 



LATERAL 

 ICONDYLE 

 )eep fascia of 



the forearm 



ANCON^EUS *. 



ENSOR CARPI 

 RADIALTS 

 LONGUS 



orsal margin 

 of ulna 



ENSOR CARPI 

 RADIALIS 

 BREVIS 



TENSOR DIOITORUM 



COMMUNIS 



EXTENSOR DIGITI 



QUINT! PROPRIUS 



EXTENSOR CARPI 

 TJLNARIS 



SOR CARPI XJLNARIS --- 



A.BDUCTOR POLLICIS 

 LONGUS 



EXTENSOR INDICIS 

 PROPRIUS 



SXTENSOR POLLICIS 



BREVIS 

 3XTENSOR POLLICIS 



LONGUS 



tal carpal ligament -"tfi-- 

 EXTENSOR CARPI ) 



RADIALIS LONGUS f 



EXTENSOR CARPI \ 



RADIALIS BREVIS/ 



EXTENSOR CARPI ) 



ULNARIS / 



TRICEPS 



BRACHII 



TENDON 



BRACHIO- , 



RADIALIS 



ORIGIN OF 



SUPERFICIAL. 

 EXTENSOR 



MUSCLES 



ANNULAR LIGA- 

 MENT OK RADIUS 



ANCON^EUS 



EXTENSOR CARPI 



RADIALIS LONGUS 



Dorsal margin 



of ulna 



EXTENSOR CARPI Jr. 

 RADIALIS BREVIS 1 



SUPINATOR. ,.M 



MUSCLE 



ABDUCTOR POLLICIS 



LONGUS 



DORSAL MARGIN OF ULNA 



3. 356. SUPERFICIAL MUSCLES ON THE DORSUM 

 OP THE LEFT FOREARM. 



EXTENSOR POLLICIS 



LONGUS" 



EXTENSOR INDICIS PROPRIUS- ---i^if 



EXTENSOR POLLICIS BREVIS 1JL 



Dorsal carpal ligament -ISp* 



EXTENSOR CARPI \ 



RADIALIS LONGUS f "~ 



EXTENSOR CARPI \ ... 

 RADIALIS BREVIS / 

 EXTENSOR CARPI \ .. 



ULNARIS/ 



EXTENSOR DIGITI ) 



QUINTI PROPRIUS / 



EXTENSOR 



POLLICIS LONGUS 



EXTENSOR INDICIS 



PROPRIUS"' 



FIG. 357. DEEP MUSCLES ON THE DORSUM 

 OF THE LEFT FOREARM. 



M. Abductor Pollicis Longus. The abductor pollicis longus (O.T. extensor 

 ossis metacarpi pollicis) arises by fleshy fibres, distal to the supinator muscle, 

 from the most proximal of the narrow impressions on the lateral half of the 

 dorsal surface of the ulna; from the middle third of the dorsal surface of 



