THE HOCK JOINT 115 



Of these there are also four, namely, the external and internal laterals, 

 the anterior common, and the posterior common. 



The external lateral ligament consists of two fasciculi termed re- 

 spectively, superficial and deep. The superficial division is cord-like 

 superiorly, but becomes flattened out towards its inferior extremity. 

 It arises from the outer surface of the external malleolus of the tibia — 

 from the portion which is placed posteriorly to the groove through 

 which the tendon of the peroneus muscle plays. The ligament passes 

 downwards and becomes attached to the astragalus, calcis, cuboid, 

 scaphoid, cuneiform magnum, and to the large and outer small 

 metatarsal bones. Posteriorly, and towards its inferior end, its fibres 

 are confounded with the calcaneo-metatarsal ligament, whilst it is 

 related superficially to the tendon of the peroneus muscle which 

 partially conceals it from view. The deep division of the external 

 lateral ligament arises from the front of the outer aspect of the 

 external malleolus anteriorly to the groove for the peroneus. It is 

 much shorter than the superficial division and takes a course which is 

 downwards and backwards, to be inserted into the outer aspect of 

 the calcis and astragalus. The deep face of this division is lined by 

 the synovial membrane of the true hock joint. From the directions 

 which the two divisions take it will be seen that they cross one 

 another like the arms of the letter X. 



The internal lateral ligament is made up of three divisions which 

 are termed respectively superficial, middle, and deep, owing to the 

 fact that they are superposed to one another. All three divisions 

 arise from the roughened surface of the internal malleolus of the tibia. 



The superficial division is the longest and it is also much the most 

 powerful. As it descends it diminishes in size and becomes inserted 

 into the tubercle of the astragalus, the scaphoid, cuneiform magnum, 

 cuneiform parvum, and the large and inner small metatarsal bones, its 

 fibres becoming confounded with those of the astragalo-metatarsal and 

 tarso-metatarsal ligaments in the manner already described. The middle 



