THE ERECT POSITION. 



61 



the flexion, anterior or posterior, of the tibio-tarsal articula- 

 tion, the surfaces and ligaments of which only permit an un- 

 stable equilibrium of the body upon the feet. Lastly, the 

 feet, separated from each other by a distance equal to that 



Fig. 20. The leg in standing. 



The foot resting the toes on The foot resting flat on the ' 



the ground. ground. 



which divides the heads of the femurs, complete the mechan- 

 ism by which man alone, among all living beings, stands 

 erect with his face placed vertically, and on a plane parallel 

 to that of the body, but not turned toward heaven, as has 

 been poetically said. 



In the attitude of a soldier without arms, with the heels 

 touching each other, and the feet forming nearly a right 

 angle, a stronger contraction of the muscles of the leg is 



