314 



]\ruscles of the Ami. 



51. biceps bracbii 



M. triceps 

 bracliii 



]".picoudyhis. 

 iiicdialis 



Olecranon 



M. 



aiiconaeus" 



rina 



M. Ilexor 

 :irpi uliiaris 



\r. extensor 

 cai'iji ulnaris 



Conipartinent for the 



iiiin. extensor (ligitorum" 



comniunis and extensor 



indicia proprius 



Processus styloidciis ulnae.. 



Conipartnient 

 for the m. extensor 

 dijiiti V propriu.s '' 



Tendo ni. extensoris.. 

 carpi ulnaris 



. M. brachioradialis 



M. extensor 

 arpi radialis 

 longus 



Epicoudylus 



lateralis 



M. supinator 



M. extensor 



carpi radialis 



brevis 



M. abductor pollicis 

 longus 



M. extensor pollicis 

 brevis 



extensor pollicis 

 longus 



extensor indicis 

 proprius 



Proc. styloideus 

 radii 



Lig. carpi dorsale 



M. extensor 

 _ carpi radialis 

 longus 



~-- M. extensor 

 carpi 

 radialis 

 brevis 



Os nietacarpale II 



359. Muscles 

 of the right fore- 

 arm, 



viewed from behind. 



(The m. extensor digitorum com- 

 munis has been removed.) 



M. abductor pollicis lou- 



gus (0. T. extensor ossis meta- 

 carpi pollicis) (see also Figs. 3.52, 

 3.57, 358, 360, 361 and 363). 

 Form: flat, spindle-shaped. 

 Position: on the posterior and 

 radial side of the forearm; be- 

 hind immediately upon the mem- 

 brana interossea and the radius, 

 covered by the mm. extensor 

 carpi ulnaris and extensor digi- 

 torum communis ; radialward 

 superficial passing over the mm. 

 extensores carpi radiales. Ori- 

 gin: facies dorsalis ulnae, mem- 

 brana interossea and facies dor- 

 salis radii. Insertion: the 

 fibers converge radialward and 

 downward to form a flat tendon, 

 which, at the radial side of the 

 forearm, goes between the mm. 

 extensores carpi radiales and 

 tiexor carpi radialis through the 

 first compartment of the lig. 

 carpi dorsale, partly to the m. 

 abductor pollicis brevis, partly 

 to the basis oss. nietacarpalis I. 

 Action: it opposes the thumb 

 to the other fingers and abducts 

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

 mus jtrofundus n. radialis. 



M. extensor pollicis brevis 



(0. T. extensor jirimi iuternodii 

 pollicis) (see also Figs. 355, 357, 

 358, 360 and 361). Form: 

 spindle-shaped. Position: 

 just distalward from the pre- 

 ceding muscle. Origin: mem- 

 brana interossea and facies dor- 

 salis radii. Insertion: it runs 

 exactly as does the preceding 

 nniscle and, close to it, goes 

 upon the back of the os meta- 

 carpale I to the base of the first 

 phalanx of the thumb. Action: 

 it abducts the thumb and ex- 

 tends the first phalanx of the 

 same. Innervation: ramus 

 profundus n. radialis. 



