268 



OSTEOLOGY 





up in the fresh state by the interosseous talocalcaneal ligament. The posterior 

 calcaneal articular surface is large and of an oval or oblong form. It articulates 

 with the corresponding facet on the upper surface of the calcaneus, 1 and is deeply 

 concave in the direction of its long axis which runs forward and lateralward at 

 an angle of about 45 with the median plane of the body. The middle calcaneal 

 articular surface is small, oval in form and slightly convex; it articulates with the 

 upper surface of the sustentaculum tali of the calcaneus. 



The medial surface presents at its upper part a pear-shaped articular facet for 

 the medial malleolus, continuous above w r ith the trochlea; below the articular 

 surface is a rough depression for the attachment of the deep portion of the deltoid 

 ligament of the ankle-joint. 



Trochlea for tibia 



For medial malleolus 



Neck 



Sulcus for Flex, hallucis longus 



For navicular bone 



' For plantar calcaneonavicular ligament 

 FIG. 272. Left talus, medial surface. 



Trochlea for tibia 



Neck 



Sulcus tali 



\ Posterior calcaneal articular 

 surface 



Anterior calcaneal articular surface 

 For navicular bone 



FIG. 273. Left talus, lateral surface. 



The lateral surface carries a large triangular facet, concave from above downward, 

 for articulation with the lateral malleolus; its anterior half is continuous above with 

 the trochlea ; and in front of it is a rough depression for the attachment of the ante- 

 rior talofibular ligament. Between the posterior half of the lateral border of the 

 trochlea and the posterior part of the base of the fibular articular surface is a tri- 

 angular facet (Fawcett 2 ) which comes into contact with the transverse inferior 

 tibiofibular ligament during flexion of the ankle-joint; below the base of this facet 

 is a groove which affords attachment to the posterior talofibular ligament. 



The posterior surface is narrow, and traversed by a groove running obliquely 



1 Sewell (Journal of Anatomy and Physiology, vol. xxxviii) pointed out that in about 10 per cent, of bones a small 

 triangular facet, continuous with the posterior calcaneal facet, is present at the junction of the lateral surface of the 

 body with the posterior wall of the sulcus tali. 



2 Edinburgh Medical Journal, 1895. 



