Chap. XXIIT.] THE ANKLE AND FOOT. 481 



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. 

 Adduction 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, and 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-postevior 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 displace- 

 ment 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 

 outwards, and is torn away from its attachments to 



F F 



