Muscles of the Arm. 



313 



358. Muscles of 

 the right forearm, 



viewed from behind. 



M. extensor dig'iti quiuti 

 proprius (0. T. extensor iiii- 

 nimi digiti). Form: oblong- 

 spindlesbaped , narrow. Posi- 

 tion: immediately on the ulnar 

 side of the preceding muscle, 

 fused with it above. Origin: 

 in common with the preceding- 

 muscle. Insertion: the long, 

 thin tendon runs through the 

 fifth compartment of the lig. 

 carpi dorsale and fuses on the 

 back of the hand with the tendon 

 going to the little finger from 

 m. extensor dig-itorum com- 



M. triceps 

 braehii 



Epicondylus- 

 medialis 



Olecranon.. 



anconaeus" 

 Ulna- 



M. flexor 

 carpi ulnaris 



M. extensor 

 carpi ulnaris 



the 



munis (see also Fig. 361). Ac- 

 tion: it extends the b^^ finger. 

 Innervation: ramus profundus 

 n. radialis. 



M. ancouaeus (see also Figs. 

 351^357, 359 and 360). Form: 

 flat, triangular. Position: 

 superficial on the back of the 

 forearm, hidden by the fascia 

 antibrachii , above immediately 

 adjacent to the caput mediale 

 of the m. triceps, radial ward 

 bounded by the m. extensor 

 carpi ulnaris, idnarward by the 

 ulna. Origin: epicondylus late- 

 ralis humeri. Insertion: the 

 fibers diverge to the facies dor- 

 salis ulnae. Action: it ex- 

 tends the forearm. Innerva- 

 tion: n. radialis. 



M. exteiisoi' carpi iiluaris 

 (see also Figs. 357, 359 and 361). 

 Form: flat, oblong- spindle- 

 shaped. Position: superficial 

 on the back of the forearm, 

 radialward bounded by the m. 

 extensor digitorum communis 

 and the m. extensor digiti Y 

 proprius, ulnarward above by 

 the m. anconaeus, below by the 

 ulna. Origin: epicondylus 

 lateralis humeri, lig. collaterale 

 radiale of the elbow joint and 

 fascia antibrachii, fused with its 

 neighbors ; also by a thin , ten- 

 dinous leaf from the facies dor- 

 salis idnao. Insertion: the 

 fibers run ulnarward and down- 

 ward to the facies dorsalis ulnae 



and upon this go over into a long tendon, ^vhich runs through 

 carpi dorsale to the basis oss. metacarpalis V. Action: 

 Innervation: ramus profundus n. radialis. 



M. biceps braehii 



M. brachioradialis 



yi. extensor carpi 

 radialis longus 



Epicondylus 

 lateralis 



M. extensor 

 carpi radialis 



brevis 



M. extensor 

 digitorum 

 communis 



M. extensor 

 digiti V proprius 



M. abductor 

 pollicis longus 



M. extensor 

 pollicis brevis 



Processus styloideus ulnae 



Ligamentnm carpi dorsa 



Processus styloi 

 radii 



M. extensor 



pollicis longui 



31. extensor c 



radialis bre\ 



M. extenso] 



carpi radiali 



longus 

 M. extensor' 

 pollicis brev 



lig. 

 hand. 



the sixth compartment of the 

 it extends and adducts the 



