428 



HUMAN ANATOMY. 



cuneiform. The middle cuneiform articulates with the scaphoid, the internal and 

 external cuneiforms, and the second metatarsal. 



Development. — One centre appears in the fourth year. 



THE EXTERNAL CUNEIFORM. 



The external cuneiform,' seen from above, is much longer than broad, with a 

 very oblique proximal border slanting outward and backward, an anterior border 

 running less obliquely in the same direction, an inner one close against the middle 

 bone in its proximal third or one-half, then receding from it and extending onto the 

 outer side of the second metatarsal, and an outer border first running forward and 

 outward against the cuboid, and then forward not quite against it, but overlapping 

 the fourth metatarsal. The ridge constituting the inferior surface does not quite 

 reach the proximal end. The posterior surface, wholly articular, is oblong, with 

 the long axis vertical, and often a little convex. The anterior surface, articular for 

 the third metatarsal, is triangular and about plane. Its inner border rises higher 

 than the outer. The internal surface articulates with the second cuneiform bone by 



Fig. 444. 



Second 

 metatarsal 



Middle 



cuneiform 

 Scaphoid 



Cuboid 



Fourth 



metatarsal 

 Third 



metatarsal 



Right external cuneiform. A, inner aspect ; B, outer aspect. 



one or two corresponding facets, as the case may be, and has, in addition, a facet for 

 the outer side of the base of the second metatarsal at the front upper angle, and 

 often extending down the border ; or the middle portion may be wanting. In the 

 middle of the surface is a roughness for the interosseous ligament. The external 

 surface is chiefly rough, giving origin to an interosseous ligament for the cuboid ; 

 at the upper proximal angle is a large facet for the same bone, and at the distal 

 upper angle there may or may not be a small one for the side of the fourth meta- 

 tarsal. The external cuneiform articulates with the scaphoid, the middle cuneiform, 

 the cuboid, and the second, third, and fourth metatarsals. 



Development. — Ossification begins in the first year. 



The Intercuneiform Bone. — On the dorsum there is a little pit which we 

 have called the intercuneiform, fossa, situated between the proximal portions of the 

 internal and middle cuneiform bones, usually more at the expense of the latter than 

 of the former. We have at least twice seen a separate ossicle, the intercuneiform 

 bone,'' in this fossa. The better specimen was wedge-shaped, its length exceeding 

 one centimetre. It clearly was more intimately related to the middle than to the 

 internal cuneiform. Pfitzner has since seen it fused with the former. 



THE METATARSAL BONES. 



Of these five bones ^ the first is very much the largest, although the shortest. 

 The second is the longest, and the others of about equal length. 



The first metatarsal bone has a concave base corresponding to the facet on 

 the internal cuneiform, which is prolonged down into a point {tuberosity) rather 

 to the outer side, on the external aspect of which the peroneus longus is inserted 

 into a round impression. On the inner side of the base is a small prominence for 

 ' the tibialis anticus. A smooth facet for the second metatarsal is often found on the 

 outer side. A groove for the capsular ligament more or less perfecdy encircles the 



'Anat. Anzeiger, Bd. x.x., 1902. 



^Os cuneiforme tertium. 'Ossa metatarsalia 1-V. 



