230 THE ERECT POSITION IN MAN. 



nally in the three outer toes. The inner column, commencing 

 behind, and above, and on the inner side in the astragalus at 

 the ankle, terminates, in front and inwards, in the hallux 

 and second and third toes. 



e. The integument of the sole of the animal plantigrade 

 foot presents a pad for the heel, and pads below the metatarso- 

 phalangeal joints. The sole of the human foot has three pads 

 only, one for the heel, the other two corresponding to the 

 metatarso-phalangeal portions of its two composite columns. 

 The sole of the human foot is therefore peculiar, in presenting 

 a strongly marked integumentary groove or fold indicating the 

 distinct action of its two columns (Fig. 13). 



/. A line, extending from the outer part of the back of the 

 heel to the point of the hallux, indicates the dynamic or 

 proper axis of the human foot. 



g. In full extension of the ankle-joint, along with longi- 

 tudinal curvature of the dorsum of the foot and complete 

 extension of the great toe, that portion of the axis of the foot 

 behind the great toe, may be brought almost in a line parallel 

 to the line of gravity. No animal foot permits of such an 

 amount of extension. 



h. The human foot is a tripod, the heel and inner pad 

 being its fixed points, the outer pad the adjustable point. 



i. The human ankle joint is the only complete ankle joint; 

 it alone possesses a complete extensor area. 



j. In man alone is the astragalus permitted by the 

 completion of its articular connections with the calcaneum, 

 scaphoid, and cuboid, to determine those delicate rocking and 

 oblique movements of the human foot, which condition also 

 the varied inclinatures of the limb and body on the foot. 



h The structure in the ape corresponding to the human 

 foot is a foot-hand, or manu-pcd. Presenting the fundamental 

 type of the foot of the mammal, it is so modified as to form a 

 clasping instrument. In certain respects it more nearly 



