PELVIC LIMBS 751 



anterior and the middle third of the tibial aspect is the lesser process, 

 or sustentaculum, a semicircular shelf-like projection directed distally 

 and toward the dorsal side. Its dorsal surface is concave, and forms 

 part of the dorsal surface of the bone ; its tibial surface is convex, 

 and gives attachment to the inferior calcaneo-scaphoid ligament ; its 

 plantar surface is deeply grooved to transmit the tendon of the flexor 

 longus digitorum muscle. 



Distal to the lesser process, the tibial surface is rough for the 

 attachment of the inferior calcaneo-scaphoid ligament. At its dorsal 

 margin is seen the expansion of the front of the tibial facet on the 

 dorsal surface. At its distal margin is a small facet, which articulates 

 with a facet on the fibular border of the scaphoid near its proximal 

 end. 



The distal surface (Fig. 567) is a smooth, round, or oblong artic- 

 ular surface for the cuboid ; it is almost flat, or slightly concave, from 

 above downward, and convex from side to side, and faces to the tibial 



FIG. 567. 

 Dorsal Side. 



With Astragalus. 



Lesser Process, _ 

 with Astragalus. H^ 



Side. WY , I-'' Side 



With Scaphoid. Greater Process, 



with Cuboid. 



Plantar Side. 



LEFT CALCANEUM, DISTAL ASPECT. 



side as well as distally. Its margins are arcuate, but the tibial is not 

 well defined, and bears a flattened triangular area which joins the 

 fibular side of the proximal surface of the scaphoid. 



The proximal surface is oval, with the long diameter vertical. Its 

 lateral margins are prominent and swollen into more or less marked 

 tuberosities. Of these, the inner, or tibial, is the larger. The 

 plantar border is rounded. Almost the entire proximal surface is 

 occupied by a wide, vertical groove, in which lies the tendon of the 

 great extensor muscle of the foot. Just above the plantar margin is 

 a curved line, which marks the dorsal limit of the insertion of this 



