PELVIC LIMBS 743 







proximal surface faces at first dorsally and proximally, and then proxi- 

 mally and to the plantar side. 



The tibial or internal surface (Fig. 561) differs from the external 

 in lying in one plane, and therefore cannot be well divided into parts 

 for the body, the neck, and the head. It is limited at the proximal 

 end and at the proximal half of the dorsal margin by the arcuate edge 

 of the trochlea ; the distal half of the dorsal margin is emarginate as 

 far as the end of the head. The distal margin is arcuate, and the 

 plantar border is arcuate for the distal half and emarginate for the 

 proximal half. Along the proximal and dorsal margins is a narrow 



FIG. 560. 

 Proximal Side. 



With Tibia. 



Side. 



Head, with Scaphoid. 



Distal Side. 



LEFT ASTRAGALUS, DORSAL SURFACE. 



facet for the fibular side of the internal malleolus. This facet is narrow 

 where it begins at the proximo-plantar angle and expands at the dorsal 

 end. On the plantar side of the facet is a rough area for the insertion 

 of a ligament. Distal to this area, where the neck begins, is a pit, 

 marked by a number of small foramina. The surface of the neck is 

 slightly rough ; it is encroached upon at the distal and plantar side 

 by that extension of the articular surface of the head which joins the 

 tuberosity of the scaphoid. 



The distal or anterior surface (Fig. 562) is limited to the front 

 of the head ; it is oval, the large diameter running obliquely from 

 the tibial side dorsally and to the fibular side. The margins are all 

 rounded, and are seen on the other aspects of the head. The surface 

 is convex in both directions, and fits into a corresponding concave 

 surface on the proximal surface of the scaphoid. 



