310 



Muscles of the Arm. 



Ihunerus 



tiicips braehii 

 raiiut medialei 



Scjitum 



inteniiusculaie 



niL'diale 



M. extensor carpi f _ ^ 

 radialis longns ( 



pronator 



teres 



M. supinator- 



M. extensor earpi 

 radialis ))revis 



Origin 



from the 



epicondjius 



niedialis 



hnineri 



M. flexor' 

 digitornm 

 profundus 



M. flexor pollicis , 

 longus I 



M. iironator t 



<|iiadratus f 



'i 



M. alHluctiir pollicis i 

 Idiigus 





f-oC carpi 

 lig,dllis 



M.. !,-or _ 

 poUii 1-- liiHvis" 



Teiulo 

 ni. Ilcxoris .. 

 pollicis loiii;! 



tlio mill. Ilexoros dij, 

 the in. tiexor jiollicis 

 it flexes the 2iid phal 



355. Muscles of 

 the right forearm 



(.3-^ layerj, 



viewed from in front. 



(The mm. biceps, brachialis, brachio- 

 radialis* flexor earpi radialis, pal- 

 raaris longus and flexor digitorum 

 sublimis have been removed; the 

 lig. carpi transversum has also been 

 removed.) 



M. flexor digitorum profundus 



(see also I'igs. 353, 354 and 356). 

 Form: flat, spindle-shaped. Posi- 

 tion: on the volar surface of the 

 forearm, directly upon the ulna and 

 ra. pronator- qiiadratus; completely 

 covered by the mm. pronator teres, 

 flexor car]u radialis, palmaris longus, 

 flexor digitorum sublimis and flexor 

 carpi ulnaris. Origin: facies volaris 

 antl niedialis ulnae and membrana 

 iuterossea antibrachii. Insertion: 

 the fibers run parallel downward: 

 from the muscle belly, from the middle 

 of the forearm on, go off four long, 

 flat tendons, which go beneath and 

 along with the tendons of the m. 

 flexor sublimis, under the lig. carpi 

 transversum to the hollow of the 

 hand and thence to the 2nd_5th 

 finger: each tendon runs, at the 

 level of the l^t phalanx, between the 

 halves of the chiasma tendinum of 

 the corresponding tendon of the m. 

 flexor sublimis to the base of the 

 3rd phalanx (see Fig. 364). Action : 

 it flexes the 2"* and 3"i phalanx of 

 the 2"d 5*1' finger. Innervation : 

 ulnar half (for the 4''^ and S^ii finger i : 

 u. ulnaris; radial half (for the 2"^ 

 and 3rd linger) : n. interosseus volaris 

 of the u. medianus. 



M. flexor pollicis longus isee 

 also Figs. 354 and 356). F o r m : flat, 

 oblong-triangular. Position: on the 

 volar surface of the forearm, immedia- 

 tely upon the radius and the m. pro- 

 nator quadratus ; covered by the mm. 

 liroiiatur teres, brachioradialis, flexor 

 carpi radialis and flexor digitorum 

 sublimis. Origin: facies volaris radii 

 and usually, by a thin bundle, from 

 the e])icondylus niedialis humeri. In- 

 sertion: the fibers run to a long 

 tendon beginning ulnarward; this 

 extends, ahmg with the tendons of 

 itorum, below the lig. carpi transversum to the hand, tlien in the groove of 

 brevis to the base of the 2"d phalanx of the thumb (see Fig. 364). Action: 

 anx of the thumb. I n n e r v a t i >' n : n. interosseus volaris of the n. medianus. 



il. Hex or 

 carpi ulnaris 

 (drawn aside) 



M. flexor 

 earpi ulnaris 



Tendines ni. flexoris 

 digitorum profundi 



- Os pisiforme 



Hamulus ossis liamati 



Insertion of the 



m. flexor carpi 



radialis to the basis 



iiss. metacarjialis 1 1 



