Muscles of the Arm. 



309 



354. Muscles 

 of the right fore- 

 arm (2'"^^ layer), 

 viewed from in front. 



(The mm. bracliioradialis . pru- 

 nator teres, flexor carpi radialis, 

 palmaris longus and flexor carpi 

 ulnaris have been removed; the 

 lig. carpi transversum lias been 

 cut through.) 



M. flexor digitoruin subli- 



mis (see also Fig. 352). Form: 

 flat, spindle-shaped. Position: 

 on the volar surface of the fore- 

 arm ; above, it is covered by the 

 mm. brachioradialis , pronator 

 teres, flexor carpi radialis, pal- 

 maris longus and flexor carpi 

 ulnaris ; below, it lies between the 

 mm. flexores carpi radialis et 

 ulnaris, coming to the surface 

 and overlapped only by the m. 

 palmaris longus. Origin: partly 

 fi'om the epicondylus medialis 

 humeri and fi'om the proc. co- 

 ronoideus ulnae , fused with its 

 neighbors (caput humerale), 

 partly from the facies volaris 

 radii (caput radiale) and, 

 between, from a tendinous arch, 

 which bridges over the a: ul- 

 naris and the n. medianus. 

 Insertion: the fibers converge 

 down^vard to form four, different, 

 widely separated muscle -bellies, 

 from the distal ends of which 

 emerge four flat , long tendons ; 

 these extend, so that those 

 destined for the S^''^ and 4t'i finger 

 lie superficially, beneath the lig. 

 carpi transversum to the hand ; 

 thence all diverge to the volar 

 surfaces of the 2nd 5tti finger 

 (see Figs. 363 and 364). On 

 the volar surface of the first 

 phalanx each tendon divides into 

 two halves, which surround the 

 correspondiiig tendon of the m. 

 flexor digitorum profundus (chi- 

 asma tcndiimm.) ; the two halves 

 nnile again bebiud the same on 

 the volar surface of the base of 

 the second plialanx, where they 

 become attached. Action: it 

 flexes the 2"d phalanx of the 

 2nd 5th finger. Innervation : 

 n. medianus. 



Tendo lu, 

 bicipitis 

 braclui 



M. 

 extensor 



carpi 

 radialis 

 longus 



Tuberositas 

 radii 



M. 

 supinator 



M. pronator 

 quadratus 



M. flexor digi- 

 torum profundus 



j\r. flexor 

 car[)i radialis 

 (cut through) 



Ligamentuni 



carpi 



transversum 



(reflected,! 



M. 



abductor 



pollicis 



brevis 



M. 

 flexor 



digit. 



pro- 

 fund. 



M. brachialis 



.Epicondylus^" 

 medialis 



M. flexor 



digitorum 



sublimis 



(caput 

 humerale) 



Space for the 



passage of the 



a. ulnaris and 



the n. medianus 



M. flexor 



digitorum 



sublimis 



(caput radiale) 



M. flexor 

 digitorum 



sublimis 



xor 



Inaris 

 (cut through) 



- Os pisiforuu' 



Ligamentum carpi 



transversum 



(reflected) 



M. abductor 

 digiti quinti 



Tendines 

 m. flexoris 

 digitorum 



sublimis 



II III IV V 



