ARTICULATION OF THE ANKLE. 



223 



and to show these, the peronei muscles, and the remains of the 

 annular ligament below the outer malleolus, should be taken away. 



The anterior ligament is a thin fibrous membrane, which is 

 attached to the tibia close to the articular surface, and to the upper 

 part of the astragalus near the articulation with the iiavicular bone. 

 In the ligament are some rounded intervals and apertures for vessels. 

 On the sides it joins the lateral ligaments. 



The posterior ligament is thinner than the anterior, and is attached 

 to the tibia and astragalus, close to the articular surfaces of the 

 bones. Towards the outer 

 side it consists of transverse 

 fibres, which are fixed into 

 the hollow on the inner side 

 of the external malleolus. 



The internal lateral or 

 ddtuid ligament (fig. 85) 

 is attached by its upper, 

 smaller end to the inner 

 malleolus, and by its base 

 to the tarsal bones, by fibres 

 which radiate to their inser- 

 tion in this manner : The 

 posterior (*) are directed to 

 the hinder part of the inner 

 surface of the astragalus ; 

 the middle ( 2 ) pass verti- 



Anterior 

 ligament 

 thin and 

 imperfect. 



Posterior 

 ligament. 



cully to the sustentaculum 

 tali of the os calcis ; and 

 the anterior ( a ), which are 

 thin and oblique, join the 

 internal calcaneo-navicular 



Internal or 

 deltoid : 



attach- 

 ments. 



FIG. 86. EXTERNAL LATERAL LIGAMENT OP 

 THE ANKLE (ALTERED FROM BOURGERY). 



1. Anterior part, 2, posterior part, ami 

 3, middle part of the outer ligament. 



4. Interosseous of astragalus and os 

 ligament and the inner side ca i c i s> 



of the navicular bone. The 5. External calcaneo-navicular ligament. 



tendons of the tibialis pos- 



ticns and fiexor longus digitorum are in contact with this ligament. 



The external lateral ligament (fig. 86) consists of three separate 

 pieces, anterior, middle, and posterior, which are attached to 

 the astragalus and the os calcis. The anterior piece (*) is a short 

 fiat band, which is directed from the fore part of the malleolus to 

 the side of the astragalus in front of the lateral articular surface. 

 The middle portion ( 3 ) descends from the tip of the malleolus to the middle, 

 outer surface of the os calcis, about the middle. The posterior ( 2 ) 

 is the strongest, and is almost horizontal in direction ; it is fixed 

 externally to the pit on the inner surface of the malleolus, and is 

 inserted into the external tubercle and adjoining posterior part 

 of the external surface of the astragalus behind the lateral articular 

 facet. 



The posterior and middle fasciculi are placed beneath the peronei relations, 

 muscles. The middle piece is but slightly in contact above with 

 ^the synovial membrane of the ankle-joint ; and both it and the 



External 

 has three 

 pieces : 



anterior, 



and pos- 

 terior ; 



