THE FOOT. 225 



from the back of the leg, of which that of the flexor longus pol- 

 iicis pedis makes a conspicuous groove on the under surface of 

 the little aphophysis. 



Of the Astragalus, (UJlstragah.) 



This is the next in size to the os calcis, and is placed on the 

 superior part of the latter, between it and the bones of the leg, 



The astragalus presents, above, a semi-cylindrical surface, 

 by which it is put in contact with the tibia. This surface is 

 narrower, and continued farther behind than it is before; is 

 slightly depressed, longitudinally, in its middle, and, conse- 

 quently, presents an elevated margin on either side, of which 

 the external is the broadest and highest. This articular face 

 continues on each side of the bone, and is more extensive ex- 

 ternally, where it comes in contact with the fibula or malleolus 

 externus, than internally, where it touches the 'malleolus in- 

 ternus. 



The inferior face of the astragalus is traversed by an oblique 

 rough fossa, going from within outwards and forwards, and 

 corresponding in size with that on the upper face of the os cal- 

 cis. Behind the fossa, and parallel to it, is a deep oblique se- 

 mi-cylindrical concavity, suited to the adjoining face of the os 

 calcis; and before the fossa is a narrow oblong convexity, 

 suited to the corresponding articular concavity of the same 

 bone. When the latter is divided into two facets, the concavi- 

 ty of the astragalus presents also two facets, separated by a 

 small ridge. 



The anterior extremity of this bone is terminated by a con- 

 vex head, the horizontal diameter of which is the greatest. 

 This head articulates with the scaphoides, and is continuous 

 with the surface that rests upon the little apophysis of the os 

 calcis. On the internal side of the head is a small triangular 

 surface, continuous with the others, that rests upon a strong 

 ligament going from the os calcis to the scaphoides. Above, 

 immediately before the surface for the tibia, is a small depres- 

 sion, which, in the flexions of the foot, receives the anterior 



