CUNEIFORM BONES. 255 



size, and its more irregular wedge-like form. "Without the others, it may be 

 known by the large kidney-shaped anterior articulating surface, and by the 

 prominence on the non-articular surface (or base of the wedge), for the attach- 

 ment of a large tendon. It presents for examination six surfaces. 



The internal surf ace is subcutaneous, and forms part of the inner border of the 

 Coot; it is broad, quadrilateral, and presents at its anterior inferior angle a 

 smooth oval facet, over which the tendon of the Tibialis Anticus muscle glides; 

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

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

 narrow 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 attach- 

 ment of ligaments, and prominent below, where it forms part of the tuberosity. 

 The anterior surface, kidney-shaped, 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 sca- 

 phoid. 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 Tibialis Anticus. The superior surface is the narrow pointed end of the 

 wedge, which is directed upwards and outwards ; it is rough for the attachment 

 of ligaments. 



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

 row edge looks upwards, and the long articular surface forwards ; the external 

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

 side to which it belongs. 



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

 metatarsal bones. 



Attachment of Muscles. The Tibialis Anticus and Tibialis Posticus. 



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

 like form, the broad extremity being placed upwards, the narrow end down- 

 wards. It is situated between the other two bones of the same name, and cor- 

 responds to the scaphoid behind, and the second metatarsal in front. It may be 

 distinguished from the external cuneiform bone, which it much resembles in 

 general appearance, by the articular facet, of angular form, 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 metatarsal bone. The posterior surface, 

 also triangular, articulates with the scaphoid. The internal surface presents an 

 articular facet, running along the superior and posterior borders for articulation 

 with the internal cuneiform, and is rough below for the attachment of liga- 

 ments. The external surface presents posteriorly a smooth facet for articulation 

 with the external cuneiform bone. The superior surface forms the base of the 

 wedge : it is quadrilateral, broader behind than in front, and rough for the 

 attachment of ligaments. The inferior surface, pointed and tubercular, is also 

 rough for ligamentous attachment. 



To ascertain to which foot the bone belongs, hold its superior or dorsal sur- 

 face upwards, the broadest edge being towards the holder : the smooth facet 

 (limited to the posterior border) will then point to the side to which it belongs. 



Articulations. With four bones : scaphoid, internal and external cuneiform, 

 and second metatarsal bone. 



The External Cuneiform, intermediate in size between the two preceding, is 

 of a very regular wedge-like form, the broad extremity being placed upwards, 

 the narrow end downwards. It occupies the centre of the front row of the 

 tarsus between the middle cuneiform internally, the cuboid externally, the sca- 

 phoid behind, and the third metatarsal in front. It is distinguished" from the 



