1 8 THE POCKET ANATOMY 



The anterior ligament is triangular in shape, and passes' 

 between the adjacent margins of the tibia and fibula. 



The posterior ligament is similarly placed upon the posterior 

 part of the articulation. 



The transverse or inferior ligament lies deep to the pre- 

 ceding, passing transversely across the back of the joint, from 

 (lie external malleolus nearly to the internal malleolus, and 

 s jrves to deepen the ankle-joint. 



The synovial membrane is continuous with that of the 

 ankle-joint. 



IV. THE ANKLE-JOINT. 



This is a ginglymus or hinge joint ; the lower ends of the 

 nbia and fibula embracing the upper articular surface of the 

 astragalus. 



The anterior ligament, broad and thin, is connected above 

 with the edge of the articular surface of the tibia, and below 

 with the margin of the superior articular surface of the astra- 

 galus. 



The posterior ligament consists principally of transverse 

 fibres, which blend above with the transverse ligament of the 

 inferiortibio-fibular articulation, and are attached to the back 

 part of the upper articular surface of the astragalus. 



The internal lateral or deltoid ligament consists of two 

 parts. The superficial part is attached by its apex to the 

 internal malleolus, and by its base posteriorly to the inner 

 side of the astragalus, the sustentaculi tali, and anteriorly to 

 the tuberosity of the scaphoid, blending with the inferior 

 calcaneo-scaphoid ligament. The deep part passes from the 

 apex of the inner malleolus to the inner side of the astragalus. 



The external lateral ligament consists of three bundles of 

 fibres. The anterior slip passes between the front of the 

 external malleolus and the side of the astragalus in front of 

 the superior articular process. The middle passes from the 

 apex of the outer malleolus to the middle of the outer side of 

 the os calcis. The posterior is attached to the bone just behind 

 the deep groove on the posterior part of the outer malleolus, 

 running transversely inwards to a depression on the posterior 

 surface of the astragalus. 



The synovial membrane lines the inner surface of the 

 ligaments, and is reflected on to the articular surfaces of" 

 the bones. It also lines the inferior tibio-fibular articula- 

 tion. 



