90 THE ANATOMY OF THE HORSE. 



lateral ligamejits ; and it communicates with the synovial membrane 

 that lubricates the articulations between the os calcis and the astragalus 

 on the one hand, and the cuboid and scaphoid on the other. It also 

 sometimes supplies the two upper facets between the os calcis and 

 astragalus. 



Directions. — The anterior and posterior ligaments should be incised 

 in order to expose the synovial membrane ; and, therefore, these and 

 the lateral ligaments should be cut away. This will effect the separa- 

 tion of the tibia, and the next group of ligaments may then be 

 examined. 



The following ligaments can hardly be classified as belonging specially 

 to any one articulation or set of articulations. For the most part they 

 bind together the series of tarsal bones, and also serve to bind these to 

 the metatarsal bones. 



The Astragalo-metatarsal Ligament. — This is a flat, radiating ligament, 

 ►situated on the inner side of the tarsus. Its fibres are attached above 

 to the tubercle on the inner side of the astragalus ; and, widening as it 

 descends, it becomes inserted into the scaphoid, cuneiform magnum, 

 and large metatarsal bone. 



The C alcaneo-metatarsal or Calcaneocuboid Ligament. — This is a 

 strong, cord-like ligament, situated at the outer side of the back of the 

 hock, and attached to the posterior border of the os calcis, the cuboid, 

 and the head of the external small metatarsal bone. 



The Tarso-metatarsal Ligament will be seen covering the tarsal bones 

 at the back of the hock. It forms a thick mass of fibrous tissue 

 intimately adherent to these bones and to the heads of the metatarsal 

 bones. Its inner border is blended with the lateral ligament of the 

 tibio-tarsal joint ; and its outer with the calcaneo-metatarsal ligament. 

 Below it is continued as the subtarsal ligament, which joins the per- 

 forans tendon. The anterior face of the ligament, where not adherent 

 to the bones, is lined by synovial membrane ; and its posterior face is 

 similarly lined by the synovial membrane of the tarsal sheath. 



Directions. — At the front of the hock the point of a scalpel should be 

 introduced into the articulation between the astragalus and the 

 scaphoid : and, by cutting round the hock through the three ligaments 

 just described, an attempt should be made to separate the astragalus 

 and os calcis, as a single piece, from the rest of the tarsal bones. Before 

 this can be effected, however, there must be cut an interosseous ligament, 

 which is composed of short and strong fibres passing between the os 

 calcis and astragalus on the one hand, and the cuboid and scaphoid on 

 the other. At the same time the synovial membrane belonging to the 

 articulations between these two sets of bones will be opened into. This 

 capsule communicates in front with that of the tibio-tarsal joint, and " is 

 prolonged superiorly between the calcis and astragalus, to lubricate two 



