Chap, xxii L] THE ANKLE AND FOOT. 479 



3. The dislocation upwards. In this rare accident 

 the inferior tibio-fibular ligaments are ruptured, the 

 two bones are widely separated at their lower ends, 

 and the astragalus is driven up between them. The 

 anterior and posterior ligaments are entirely rup- 

 tured, but the lateral ligaments usually escape with 

 but some slight aceration. The accident appears to 

 be generally caused by a fall, the patient alighting flat 

 upon the soles of the feet. Mr. Bryant records a case 

 in which both feet were similarly dislocated upwards. 



The foot. There are two arches in the foot, an 

 antero-posterior and a transverse. 



1. The antero-posterior arch has its summit at the 

 astragalus and ankle-joint. It may be considered 



Fig. 55. Antero-Posterior Section of the Foot (Eiidinger). 



1, Tibia; 2, astragalus; 3, oscalcis: 4, scaphoid; 5, int. cuneiform; 6, first 

 mctatarsal bone ; 7 and 8, phalanges of great toe. 



as composed of two piers. The hinder pier contains 

 the posterior parts of the astragalus and os calcis, the 

 anterior pier the remainder of those bones with the 

 rest of the tarsus, the metatarsus, and the phalanges 

 (Fig. 55). 



