THE HOCK JOINT 113 



The second set are the Calcaneo-Astragaloid Ligaments which, as 

 may be inferred from the name, serve to bind the calcis and astragalus 

 together. Of these h'gaments there are four, namely, a superior 

 ligament which passes from one bone to the other above the articular 

 surfaces and which consists of short but powerful fibres. Two other 

 ligaments connect the sides of the bones and are hence called the 

 laterals, whilst a fourth strong ijiterosseous ligament connects the two 

 non-articular areas of the bones which are placed on their surfaces 

 which come into apposition with one another. 



The several bones of the tarsus are thus united into two sets, each 

 of which, for our purposes, may be regarded as a single bone. The 

 upper set consists of the calcis and astragalus, and the lower set of the 

 cuboid, scaphoid, and the cuneiform bones. 



We shall now proceed to consider the group of ligaments uniting 

 these two already-united sets of bones together. Of these there are 

 four, and they are of great importance. Firstly we have the astragalo- 

 scaphoid ligament, which is interosseous in position and runs from 

 the non-articular area on the inferior aspect of the astragalus, which 

 forms its superior attachment, to the superior surface of the scaphoid 

 to which the ligament is attached inferiorly. The astragalo-metatarsal 

 ligament — another member of this group, arises from the tubercle on 

 the inner surface of the astragalus. It passes obliquely downwards 

 and forwards, its fibres spreading out as we descend so that they 

 present a fan-like arrangement. The ligament passes over the anterior 

 borders of the scaphoid and cuneiform magnum, to which some of 

 its fibres are attached, and it ultimately obtains insertion into the 

 anterior face of the upper end of the large metatarsal bone just below 

 its articular surface. The most posterior of the fibres of this ligament 

 are confounded with those of the superficial division of the internal 

 lateral ligament which is one of the common ligaments of the joint. 

 The astragalo-metatarsal ligament, therefore, crosses the seat of spavin, 

 and has before been referred to. 



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