THE FOOT 



243 



articular surface of the astragalus; below, it is grooved for the tendon of the Flexor 

 longus hallucis. Its free margin is rough, for the attachment of part of the 

 internal lateral ligament of the ankle-joint. 



The anterior surface (fades ariicularis cuboidea), of a somewhat triangular 

 form, articulates with the cuboid. It is concave from above downward and out- 

 ward, and convex in the opposite direction. Its inner border gives attachment 

 to the inferior calcaneoscaphoid ligament. 



Groove for Peroneus brevis 



Peroneal tubercle 



i 

 Groove for Peroneus longua 



For tendoAchillis 



External tubercle 



For posterior facet of astragalus 

 For middle facet of astragalus 



For anterior facet of astragalus 



Internal tubercle 

 Groove for Flexor longus Jiallucis 



Sustentaculum tali 



For cuboid 



Groove for interosseous ligament 



FIG. 194. The left os calcis. A. Postero-external view. B. Antero-internal view. 



The posterior surface is rough, prominent, convex, and wider below than above. 

 The posterior extremity is the projection of the heel. It is called the tuberosity 

 (tuber calcanei). Its lower part is rough, for the attachment of the tendo Achillis 

 and the tendon of the Plantaris muscle; its upper part is smooth, and is covered 

 by a bursa which separates the tendons from the bone. 



