MUSCLES OF THE FOREARM. 



the forearm, turn aside the integuments and this muscle 

 will be exposed. 



It arises tendinous and fleshy from the ridge leading to 

 the external condyle, commencing a little below the inser- 

 tion of the deltoid, also from the inter-muscular ligaments- 

 FIG. 229. A thick muscle is formed, which de- 



scends along the outer part of the elbow, 

 and at the middle of the fore-arm termi- 

 nates in a flat tendon, which is inserted 

 upon the styloid side of the radius. 



Function. To supinate or turn the 

 palm of the hand upward by rolling the 

 radius outward. 



Extensor carpi radialis longior (Fig. 

 229) arises from the external ridge of 

 the os humeri, between the external con- 

 dyle and supinator longus, tendinous and 

 fleshy. A thick, short belly is formed^ 

 which about the middle of the radius 

 ends in a flat tendon, which passes under 

 the posterior annular ligament and over 

 the wrist, to be inserted into the poste- 

 rior part of the root of the metacarpal 

 bone of the fore-finger. A bursa is seen 

 surrounding the tendon of this muscle 

 under the annular ligament, and another 

 at its insertion. 

 Function. To extend the wrist and hand. 

 Extensor carpi radialis brevior (Fig. 229) arises from 

 the external condyle and external lateral ligament, tendi- 

 nous and fleshy. A thick fleshy belly is formed, situated 



FIG. 229 represents the muscles on the back of the forearm, a Inferior 

 portion of the biceps, b Inferior portion of the brachialis anticus. c Inferior 

 portion of the triceps, d Supinator radii longus. e Extensor carpi radialis 

 longior. /Extensor carpi radialis brevior. g Tendinous insertions of these 

 two latter muscles, h Extensor communis digitorum. i Auricularis, a portion 

 of extensor communis. j Extensor carpi ulnaris. fcAnconeus. / Flexor carpi 

 ulnaris. m Extensor minor pollicis. n Extensor major pollicis. o Posterior 

 annular ligament. 



