THE NAVICULAR BONE. 



31 



¥lG. 19. — Anteio- 

 superior surface 

 vt navicular 



bone. 



Fig. 20.— Postero-inferior 

 surface of navicular 

 bone. a, anterior 

 border ; b, tendinous 

 surface. 



the conformation of the articular surface of the pedal bone. 

 The posterior surface is more extensive than the anterior, and it 

 looks downwards as well as backwards. Generally it resembles 

 the anterior, but is not so smooth. Over this surface the flexor 

 pedis perforans tendon plays. Of the two edges the upper is 

 less extensive, rough and porous in appearance, and receives 

 the insertion of the postero- 

 lateral lioaments of the cottin 

 joint. (To be afterwards de- 

 scribed.) The lower edge is 

 divided into two portions — 

 one, the anterior, carries a 

 narrow, elongated smooth 

 area for articulation with the pedal bone, the other, or posterior 

 poition, is rough, showing the openings of numerous small 

 canals, and provided for the insertion of the interosseous liga- 

 ment that binds the navicular to the pedal bone. The two 

 extremities of the bone, inner and outer, are bluntly rounded 

 and tapering, and show nothing worthy of note. 



The foregoing remarks on the bones of the foot apply equally 

 to the fore and hind extremities. It need only be remarked 

 that the bones of the hind foot are somewhat longer and more 

 slender than those of the fore. The posterior os pedis, being 

 laterally compressed, has a more upright appearance, while its 

 plantar surface is more concave than that of the fore-limb. 



