540 



The First Layer. 



Abductor hallucis. Flexor brevis digitorum. 



Abductor minimi digiti. 



Dissection. Remove the fascia on the inner and outer sides of the foot, commencing in 

 front over the tendons and proceeding backward. The central portion should be divided 

 transversely in the middle of the foot, and the two flaps dissected forward and backward. 



The Abductor hallucis (m. abductor hallucis} lies along the inner border of the 

 foot and covers the first parts of the plantar vessels and nerves. It arises from 



the inner tubercle on the under surface of the 

 os calcis ; from the internal annular ligament ; 

 from the plantar fascia; and from the inter- 

 muscular septum between it and the Flexor 

 brevis digitorum. The fibres terminate in a 

 tendon which is inserted, together with the 

 innermost tendon of the Flexor brevis hal- 

 lucis, into the inner side of the first phalanx 

 of the great toe. 



The Flexor brevis digitorum (m. flexor 

 digitorum brevis) lies in the middle of the 

 sole of the foot, immediately beneath 1 the 

 plantar fascia, with which it is firmly united. 

 Its deep surface is separated from the ex- 

 ternal plantar vessels and nerves by a thin 

 layer of fascia. It arises by a narrow ten- 

 dinous process, from the inner tubercle of the 

 os calcis, from the central part of the plantar 

 fascia, and from the intermuscular septa be- 

 tween it and the adjacent muscles. It passes 

 forward, and divides into four tendons, one for 

 each of the four outer toes. Opposite the 

 bases of the first phalanges each tendon 

 divides into two slips, to allow of the passage 

 of the corresponding tendon of the Flexor 

 longus digitorum; the two portions of the 

 tendon then unite and form a grooved chan- 

 nel for the reception of the accompanying 

 long Flexor tendon. Finally, they divide a 

 second time, to be inserted into the middle of 

 the sides of the second phalanges. The mode 

 of division of the tendons of the Flexor 

 brevis digitorum and their insertion into 

 the phalanges is analogous to the division 

 and insertion of the Flexor sublimis digito- 

 rum in the hand. 



FIG. 398. Muscles of the sole of the foot. 

 First layer. 



Fibrous Sheaths of the Flexor Tendons. 



These are not so well marked as in the ringers. The 

 Flexor tendons of the toes as they run along the 

 phalanges are retained against the bones by a fibrous sheath, forming osseoaponeurotic 

 canals. These sheaths are formed by strong fibrous bands which arch across the tendons 



1 That is, in order of dissection of the sole of the foot. 



