262 



A MANUAL OF ANATOMY 



terior ; and the posterior surface is rather broader than the anterior, 

 and has one of the limbs of the L facet close to it. 



Articulations. — Posteriorly with the navicular, anteriorly with the 

 second metatarsal, internally with the internal cuneiform, and 

 externally with the external cuneiform. 



The external cuneiform bone, like the middle, lies with the broad 

 end of the wedge upwards, and it supports the third metatarsal. 

 The dorsal surface is rough, quadrilateral, and elongated from 

 before backwards. The plantar surface, also rough, is narrow, and 

 gives insertion to a slip of the tendon of the tibialis posticus. The 

 internal surface presents a vertical facet posteriorly for the middle 

 cuneiform, and two semi-oval facets anteriorly for articiilation with 

 the proximal pair of facets on the outer side of the base of the second 

 metatarsal. The remainder of the surface is rough and ligamen- 

 tous. The external surface has a large, almost circular, facet near 

 the postero-superior angle for the cuboid, and there may be a 



For 2nd Metatarsal 



.Posterior Surface 

 for Navicular 



For Middle Cuneiform 



— ^For 2nd Metatarsal 



For 4th Metatarsal 

 (inconstant) 



__For Cuboid 



■Anterior Surface 

 for 3rd Metatarsal 



Fig. 154. — The Right External Cuneiform Bone. 

 A, Internal View ; B, External View. 



small semi-oval facet at the antero-superior angle for the inner sid< 

 of the base of the fourth metatarsal, but this facet is not constant 

 Elsewhere the surface is rough and ligamentous. The anterio\ 

 and posterior surfaces are triangular, and covered by cartilag 

 the former articulating with the third metatarsal, and the latt 

 with the navicular. They are distinguished from each other in th 

 following manner : the anterior facet is deeper than the posterior 

 and its apex is more pointed ; the cartilage of the anterior surface 

 extends over its entire length, but the lower part of the posterior 

 surface is non-articular ; the anterior facet is slightly concavo- 

 convex from below upwards, but the posterior is concave, and it 

 has the large, almost circular, facet on the external surface con- 

 tiguous to it. 



Articulations. — Posteriorly with the navicular, anteriorly with the 

 third metatarsal, internally with the middle cuneiform and outer 

 side of the base of the second metatarsal, and externally with the 

 cuboid, and, it may be, with the inner side of the base of the fourth 

 metatarsal. 



