"766 MUSCLES OF THE FOOT. 



cle is consequently a perforans. A bursa is found with 

 this tendon at the os calcis and sole of the foot. 



Function. To bend the smaller toes and extend the foot. 



The flexor longus polUcis (Fig. 253) arises tendinous and 

 fleshy from the posterior surface of the lower two-thirds 

 of the fibula. It ends in a tendon which goes through a 

 groove in the back part of the tibia^and astragalus, con- 

 nects with the flexor longus digitorum, and goes to be 

 inserted into the last phalanx of the great toe. 



Function. To bend the great toe and extend the foot. 



A bursa is seen in connection with the tendon at the 

 astragalus, os calcis, metatarsal bone and phalanx. 



The tibialis posticus (Fig. 253) arises from the front of 

 the tibia where it connects with the fibula, and gets through 

 the interosseous ligament, arising from this latter almost 

 its whole length, as well as from the fibula and tibia adja- 

 cent to the ligament. It ends in a tendon which passes 

 behind the internal malleolus forward and inward, to be 

 inserted into the naviculare, internal cuneiform, cuboid, 

 and second and third metatarsal bones. At its insertion a 

 small sesamoid bone and bursa are seen. Function. To 

 extend the foot and turn it obliquely inward. 



MUSCLES OF THE FOOT. 



Dissection. Make an incision from the heel, along the 

 inner and outer margins of the foot ; turn down the integu- 

 ment, and then the thick adipose layer to the plantar apon- 

 eurosis. The latter being removed, the muscles are exposed. 



The muscles on the sole of the foot are divided into four 

 layers. 



FIRST LAYER. 



The abductor pollicis pedis arises, tendinous and fleshy, 

 from the internal and lower part of the os calcis, and from 

 the annular ligament, and plantar aponeurosis. Its fibres 

 run along the inner side of the foot, and are inserted into 

 the base of the first phalanx of the great toe and the inner 

 sesamoid bone. Function. To draw the great toe from 

 the others. 



