226 SKELETON. 



margin of the articular surface of that bone. The posterior 

 extremity of the astragalus is thin, and has a notch, or groove, 

 formed in it by the tendon of the flexor longus pollicis. 



Of the Naviculare, or Scaphoides, (Scaphoide.) 



It is situated at the internal side of the tarsus, between the 

 astragalus and the cuneiform bones, and has its greatest dia- 

 meter transverse. Its circumference is oval, thicker above 

 than below, and at its internal side presents a large tuberosity; 

 into which is inserted the tendon of the tibialis posticus. Some- 

 times the external margin has a small articular face, where it 

 comes in contact with the cuboides. 



The scaphoides presents, behind, a deep concavity, which 

 receives the head of the astragalus; anteriorly, it is somewhat 

 convex, but this surface is divided by small ridges into three 

 triangular faces, for the three cuneiform bones. Of these faces 

 the internal is broader below than above; the others are broader 

 above than below. 



Of the Cuboides, (Cuboide.) 



It is situated at the external side of the tarsus, between the 

 os calcis and the metatarsal bones. Its figure is irregular; but, 

 perhaps, sufficiently indicated by its name. It is narrower 

 externally than internally, and has the posterior extremity 

 oblique. 



The superior face of the cuboides is rounded, but rough. 

 The inferior face has in its middle a broad elevated ridge run- 

 ning almost transversely, but somewhat forwards. The exter- 

 nal extremity of this ridge is marked by a trochlea, on which 

 plays the tendon of the peroneus- longus; the tendon is then con- 

 ducted along a groove between the ridge and the anterior mar- 

 gin of the bone. 



The internal face is flat, and has in its middle a circular 

 facet where it comes in contact with the cuneiforme externum. 



