Muscles of the Lower Extremity. 



201 



Deep Layer: 



M. popliteus arises from the external con- 

 dyle of the femur and the external inter- 

 articular fibro- cartilage of the knee-joint; 

 it is inserted into the inner border of the 

 tibia. (Flexes the leg and rotates it inwards.) 



M. tibialis posticus arises from the posterior 

 surface of the tibia, the interosseous "mem- 

 brane and from the inner surface of the 

 fibula; it is inserted into the tuberosity of 

 the scaphoid bone (Fig. 276, 277). (Extends 

 the tarsus and raises the inner border of 

 the foot.) 



M. flexor digitorum communis longus s. per- 

 forans. Origin of the long head: posterior 

 surface of the tibia ; of the short head, 

 usually called M. flexor accessorius : from the 

 under and inner surface of the Os calcis 

 (Fig. 275). Insert.: By four tendons from 

 which arise the M. lumbricales, into the 

 III. phalanges of the four outer toes ; oppo- 

 site the I. phalanges these tendons perforate 

 the corresponding tendons of the M. flexor 

 digit, comm. brevis. 



M. flexor Jiallucis (pollicis) longus arises 

 from the lower two -thirds of the posterior 

 surface of the fibula, and is inserted into 

 the II. phalanx of the great toe (Fig. 274). 



Heitzmann, Atlas. I. 



m II 



mm/m 



Betinaculum 



269. The Muscles at 



the Posterior Side 



of the Leg 1 . 



26 



