MUSCLES ON THE SOLE OF THE FOOT. 391 



continued down the same bone, almost to its inferior extremity, 

 by a double order of oblique fleshy fibres ; its tendon passes 

 under an annular ligament at the inner ankle. 



Inserted, into the last joint of the great toe, and, generally, 

 sends a small tendon to the os calcis. 



Use. To bend the last joint of this toe. 



On the upper surface of the foot there is one muscle, viz. 



Extensor Brevis Digitorum Pedis, 



Arises, fleshy and tendinous, from the fore and upper part of 

 the os calcis ; and soon forms a fleshy belly, divisible into four 

 portions, which send off an equal number of tendons that pass 

 over the upper part of the foot, under the tendons of the for- 

 mer. 



Inserted, by four slender tendons, into the tendinous expan- 

 sion from the extensor longus which covers the small toes, ex- 

 cept the little one ; also into the tendinous expansion from the 

 extensor pollicis, that covers the upper part of the great toe. 



Use. To extend the toes. 



Muscles on the Sole of the Foot. 



On the sole of the foot there is a strong tendinous membrane called Aponturosis 

 Plantaris, which originates from the tuberosity of the os calcis, and proceeds 

 forward to the toes, increasing gradually in breadth. 



It is divided into three portions. That in the middle is the largest ; it protects 

 and covers the short flexor muscles, and the tendons in the middle of the foot. 

 That on the outside, which covers the adductor and flexor of the little toe, it> 

 next in size. The internal portion, which covers the adductor of the great 

 toe, is the smallest. 



The edges of these portions dip down so as to separate the muscles they cover 

 from each other. They are divided into five processes, corresponding with 

 the heads of the metatarsal bones ; each of these portions is divided into two 

 bands, which are inserted into each side of the head of each metatarsal bone, 

 and the tendons, nerves, and arteries pass between them. 



Immediately under the middle portion of this aponeurosis are the common short 

 flexors of the toes, viz. 



1. Flexor Brevis Digitorum Pedis Sublimis Perforatus, 



Arises, by a narrow fleshy beginning, from the inferior and 

 posterior part of the protuberance of the os calcis, between 

 the adductors of the great and little toes, soon forms a thick 



