]\Iuscles of the Arm. 



307 



352. Muscles 

 of the right fore- 

 arm, 



viewed from in front. 



M. biceps brachii- 



M. brachialis 



Teiulo 

 m. bicipitis - 

 brachii 



:m 



. extensor 



carpi 

 radialis 



longus 



J[. brachio 

 radialis 



M. extensor 

 carpi radialis 



brevis 



M. braehioradialis (0. T. 



supinator louyus) i^see also Figs. 

 353, 357 and 358). Form: flat, 

 in the shape of a long spindle. 

 Position: superficial on the 

 lateral surface of the upper arm 

 and the volar surface of the fore- 

 arm. Origin: margo lateralis 

 humeri and septum interraus- 

 culare laterale. Ins_e_rt_i_on : 

 above, it runs between the m. 

 triceps and the m. brachialis ; be- 

 low, it is bounded behind by the 

 m. extensor carpi radialis longus, 

 ulnarward by the mm. pronator 

 teres and flexor carpi radialis anil 

 becomes attached by a long, thin, 

 flat tendon above the proc. styloi- 

 deus radii. Action: it flexes 

 the forearm and brings the hand 

 into a position midway between 

 pronation and supination. In- 

 nervation: n. radialis. 



M. palmaris loiigns (see 

 als Fig. 362) (is frequently ab- 

 sent). Form: spindle-shaped, 

 narrow. Position: superflcial 

 on the volar surface of the fore- 

 arm. Origin: epicondylus me- 

 dialis humeri and fascia anti- 

 brachii, fused with its neighbors. 

 Insertion: it extends above 

 between the mm. flexor carpi 

 radialis and flexor digitorum 

 sublimis, then dowTiward and 

 radialward upon the latter and 

 goes over by a long, thin tendon, 

 in front of the lig. carpi trans- 

 versum, into the aponeurosis pal- 

 maris. Action: it makes the 

 aponeurosis paknaris tense and 

 flexes the hand. I n n e r v a t i o n : 

 n. medianus. 



M. pronator teres (0. T. 

 pronator radii teres) (see also 

 Figs. 353 and 355). Form: 

 oblong - quadrangular. Posi- 

 tion: flexure of the elbow and 

 volar surface of the forearm. 

 <-) r i g i n : partly from the septum 

 intermusculare mediale and the 

 epicondylus medialis humeri ^ 



fcaptit humerale) , partly from 



the proc. coronoideus ulnae (cuimt ulnare) ; the two heads are usually 

 n. medianus. Insertion: the fibers run, parallel, obliquely radialward 

 become attached by a short tendon to the facies volaris and lat^-alis ra 

 pronates the forearm and flexes it. Innervation: n. medianus. 



M. abductor 

 pollicis 



longus 



M. 



abductor 

 pollici-i 

 brevis 



Epi- 

 Condylus 

 medialis 



M. 

 pronator 



teres 



Laeertus 

 fibrosus 



M. flexor 

 _ carpi 

 radialis 



_ _ M. palmaris 

 longus 



M. flexor carpi 

 ulnaris 



Cutis 



:\[. flexor 

 digitorum 

 sublimis 



Os pisiforme 



Aponeurosis 

 jialmaris 



M. p;ilniaris brevis 



separated by the 

 and downward to 

 dii. Action: it 



