206 



THE SKELETON. 



THE INTERNAL CUNEIFORM (Fig. 

 The Internal Cuneiform is the largest of the three. 



For first For second For middle 



metatarsal. 



tnetatarsal. cuneiform. 



For tendon of 

 Tibialis ant. 

 FIG. 143. The left internal cuneiform, 

 internal view. B. Postero-external view. 



For naviciilar. 



143). 



It is situated at the inner 

 side of the foot, between the navicular 

 behind and the base of the first ineta- 

 tarsal in front. It may be distin- 

 guished from the other two by its large 

 size, and by its not presenting such a 

 distinct wedge-like form. Without 

 the others it may be known by the 

 large, kidney-shaped anterior articu- 

 lating surface and by the prominence 

 on the inferior or plantar surface for 

 the attachment of the Tibialis posti- 

 cus. It presents for examination six 

 surfaces. 



The internal surface is subcuta- 

 neous, and forms part of the inner bor- 

 der of the foot ; it is broad, quadrilateral, and presents at its anterior inferior angle a 

 smoot oval facet, into which the tendon of the Tibialis anticus is partially inserted ; 

 in the rest of its extent it is rough, for the attachment of ligaments. The external 

 surface, is concave, presenting, along its superior and posterior borders, a narrow 

 reversed L-shaped surface for articulation with the middle cuneiform behind, and 

 second metatarsal bone in front; in the rest of its extent it is rough for the 

 attachment of ligaments and part of the tendon of the Peroneus longus. The 

 anterior surface, kidney-shaped, much larger than the posterior, articulates with 

 the metatarsal bone of the great toe. The posterior surface is triangular, concave, 

 and articulates with the innermost and largest of the three facets on the anterior 

 surface of the navicular. The inferior or plantar surface is rough, and presents a 

 prominent tuberosity at its back part for the attachment of part of the tendon of 

 the Tibialis posticus. It also gives attachment in front to part of the tendon of the 

 the Tibialis anticus. The superior surface is the narrow-pointed end of the wedge, 

 which is directed upward and outward ; it is rough for the attachment of ligaments. 

 To ascertain to which side the bone belongs, hold it so that its superior narrow 

 edge looks upward, and the long, kidney-shaped, articular surface forward ; the 

 external surface, marked by its vertical and horizontal articular facets, will point 

 to the side to which it belongs. 



Articulations. With four bones: navicular, middle cuneiform, first and second 

 metatarsal bones. 



Attachment of Muscles. To three: the Tibialis anticus and posticus, and 

 Peroneus longus. 



THE MIDDLE CUNEIFORM (Fig. 144). 



The Middle Cuneiform, the smallest of the three, is of very regular wedge-like 



form, the broad extremity being placed 

 upward, the narrow end downward. It is 

 situated between the other two bones of 

 the same name, and articulates with the 

 navicular behind and the second meta- 

 tarsal in front. It is smaller than the 

 external cuneiform bone, from which it 

 may be further distinguished by the L- 

 shaped articular facet, which runs round 

 the upper and back part of its inner 

 surface. 



The anterior surface, triangular in form 



and narrower than the posterior, articulates with the base of the second meta- 

 tarsal bone. The posterior surface, also triangular, articulates with the navicular. 



For int. cuneiform 



For navicular. 



For ext. cuneiform. 



FIG. 144 The left middle cuneiform. A. Antero- 

 internal view. B. Postero-external view. 



