THE LOWER LIMB 



571 



ihe inner border of the sustentaculum tali of the os calcis, inner 

 border of the internal calcaneo-navicular or spring ligament, and 

 inner part of the dorsal surface of the navicular bone. 



The external lateral ligament is composed of three distinct 

 fascicuh — anterior, middle, and posterior. 



The anterior fascicidus {astr a galo- fibular) is flat, and extends from 

 the lower part of the anterior border of the external malleolus 

 to the outer surface of the astragalus immediately in front of the 

 external facet. Its direction is forwards and inwards, and it is 

 the shortest of the three fasciculi. 



The middle fasciculus {calcaneo- fibular) , which is round, is attached 

 superiorly to the tip of the external malleolus, and interiorly to a 

 tubercle on the outer surface of the os calcis situated about the 

 centre, behind and above the peroneal spine. Its direction is down- 



Internal Lateral Ligament 



Posterior Ligament 

 of Ankle 



Posterior Astragalo- 

 calcaneal Ligament 



Long Plantar Ligament 



Inferior Calcaneo-navicular Ligament 



Fig. 267. — Ligaments of the Right Foot (Internal View). 



wards and backwards, and it is related to the tendons of the 

 peroneus longus and peroneus brevis. 



The posterior fasciculus {astragalo -fibular) is the strongest bundle 

 of the three. It is attached by one extremity to the lower part of 

 the digital fossa on the inner surface of the external malleolus 

 behind the articular facet. The other extremity is attached to the 

 upper surface of the outer tubercle on the posterior border of the 

 astragalus. Its direction is inwards and slightly backwards. 



The synovial membrane lines the inner surfaces of the liga- 

 ments in a loose manner, and it covers collections of fat (Haver- 

 sian glands) at the front and back of the joint, where it forms folds 



