272 ON THE RELATIONS OF MAN 



of the foot and the hand, observable when the carpus and 

 the tarsus are contrasted ; and there are differences of 

 degree noticeable when the proportions and the mobility 

 of the metacarpals and metatarsals, with their respective 

 digits, are compared together. 



The same two classes of differences become obvious 

 when the muscles of the hand are compared with those 

 of the foot. 



Three principal sets of muscles, called " flexors/' bend 

 the fingers and thumb, as in clenching the fist, and three 

 sets the extensors extend them, as in straightening the 

 fingers. These muscles are all " long muscles " ; that is 

 to say, the fleshy part of each, lying in and being fixed to 

 the bones of the arm, is, at the other end, continued into 

 tendons, or rounded cords, which pass into the hand, and 

 are ultimately fixed to the bones which are to be moved. 

 Thus, when the fingers are bent, the fleshy parts of the 

 flexors of the fingers, placed in the arm, contract, in virtue 

 of their peculiar endowment as muscles ; and pulling 

 the tendinous cords, connected with their ends, cause 

 them to pull down the bones of the fingers towards the 

 palm. 



Not only are the principal flexors of the fingers and of 

 the thumb long muscles, but they remain quite distinct 

 from one another through their whole length. 



In the foot, there are also three principal flexor muscles 

 of the digits or toes, and three principal extensors ; but 

 one extensor and one flexor are short muscles ; that is to 

 say, then: fleshy parts are not situated in the leg (which 

 corresponds with the arm), but in the back and in the 

 sole of the foot regions which correspond with the back 

 and the palm of the hand. 



Again, the tendons of the long flexor of the toes, and 

 of the long flexor of the great toe, when they reach the 

 sole of the foot, do not remain distinct from one another, 

 as the flexors in the palm of the hand do, but they become 

 united and commingk'd in a very curious manner while 

 their united tendons receive an accessory muscle con- 

 nected with the heel-bone. 



But perhaps the most absolutely distinctive character 

 about the muscles of the foot is the existence of what is 

 termed the peronasus longus, a long muscle fixed to the 

 outer bone of the leg, and sending its tendon to the outer 

 ankle, behind and below which it passes, and then crosses 



