182 



Muscles of the Upper Extremity. 



Tenth 



ext.carp.rad.brev. 

 Tentio 



ext carp. rad. long. 

 Teiido Hl.ext primi 

 intern. poll. 



M.ext.ossis 

 / mrtacarp.poll. 

 /S ZWo M.ext.sec. 

 / intern poll. 



Jnsertio 

 M.ext b .c|rp.rad. 



Jnsertio 



241. The Tendinous Sheaths 

 in the Palm of the Hand. 



242. The Tendinous Sheaths 

 at the Back of the Hand 



Third Layer: 



M. flexor dlyitorum profundus s. pcrforans. Orig. : Upper two thirds 

 of the inner surface of the ulna and interosseous membrane. Insert. : 

 By four tendons into the third phalanges of the second to the fifth fingers ; 

 opposite the first phalanges these tendons pass between the two slips 

 of the tendons of the Flexor sublimis. (Flexor of the III. phalanges.) 

 From the radial borders of the tendons of this muscle, in the palm of 

 the hand, the Musculi lumbricalcs arise; they run to the radial borders of 

 the first phalanges and from there to the aponeurosis on the back of 

 the fingers (see Fig. 247, 248). 



M. flexor pollicis longus. Orig.: Anterior surface of the radius. Insert.: 

 Second phalanx of the thumb (sec Fig. 247, 248). 



M. pronator quadratics. Orig.: Anterior surface of the ulna. Insert.: 

 Anterior surface of the radius (see Fig. 246). 



