Chap, xxiii.) THE ANKLE AND FOOT. 525 



calcaneo-scaphoid ligament, the two lateral ligaments 

 of the ankle, and the tendons about the part. The 

 articulation permits of adduction and abduction, and of 

 some rotation of the foot beneath the astragalus. Adduc- 

 tion is associated with some turning of the toes inwards, 

 and abduction with some turning of them outwards. 



Dislocations of the astragalus. This bone 

 is sometimes luxated alone, being separated from its 

 connections with the os calcis, the tibia, the fibula, 

 and the scaphoid bone. The displacement may be 

 either forwards, backwards, or laterally. The lateral 

 luxations are nearly always oblique, the bone passing 

 as a rule forwards as well as inwards or outwards. 

 The luxation forwards is by far the most common 

 lesion, the next in frequency being a luxation out- 

 wards and forwards. The backward displacement is 

 extremely rare. The dislocations are usually com- 

 plete, are very often compound, especially when in 

 the lateral direction, and are commonly associated 

 with fracture of the tibia or fibula, or of the astragalus 

 itself. A lateral complete dislocation is impossible 

 without fracture of one or other malleolus. In these 

 injuries the interosseous ligament between the os calcis 

 and astragalus is entirely torn, as are also a greater 

 part of the lateral ligaments of the ankle, and the 

 various bands that connect the astragalus with the os 

 calcis and scaphoid. In all instances the malleoli are 

 brought nearer to the sole. In the antero-posterior 

 luxations the foot as a rule undergoes no rotation, 

 but in the luxation of the bone forwards and outwards 

 it becomes inverted, and in the displacement forwards 

 and inwards everted. 



Dislocation of the os calcis. This bone, 

 although often fractured, is very rarely luxated. 

 When displaced, however, it is usually displaced out- 

 wards, and is torn away from its attachments to the 

 astragalus and cuboid, or from the former bone alone. 



