THE CUNEIFORM BONES. 205 



To ascertain to which foot the bone belongs, hold it so that its under surface, 

 marked by the peroneal groove, looks downward, and the large concavo-convex 

 articular surface backward toward the holder : the narrow non-articular surface, 

 marked by the commencement of the peroneal groove, will point to the side to 

 which the bone belongs. 



Articulations. With four bones : the os calcis, external cuneiform, and the 

 fourth and fifth metatarsal bones ; occasionally with the navicular. 



Attachment of Muscles. Part of the Flexor brevis hallucis and a slip from 

 the tendon of the Tibialis posticus. 



The Navicular (Fig. 142). 

 The Navicular or Scaphoid bone is situated at the inner side of the tarsus, 



For mid. cuneiform. 

 For int. ^^^^^^ 



cuneiform. ^^ p^ /cuneiform. 



For c'iboid \ 



(occasional). For astragalus. 



FIG. 142. The left navicular. A. Antero-external view. B. Postero-internal view. 



between the astragalus behind and the three cuneiform bones in front. It 

 may be distinguished by its form, being concave behind, convex and subdivided 

 into three facets in front. 



The anterior surface, of an oblong form, is convex from side to side, and sub- 

 divided by two ridges into three facets, for articulation with the three cuneiform 

 bones. The posterior surface is oval, concave, broader externally than internally, 

 and articulates with the rounded head of the astragalus. The superior surface is 

 convex from side to side, and rough for the attachment of ligaments. The 

 inferior is irregular, and also rough for the attachment of ligaments. The internal 

 surface presents a rounded tubercular eminence, the tuberosity of the navicular, 

 the lower part of which projects, and gives attachment to part of the tendon of 

 the Tibialis posticus. The external surface is rough and irregular, for the 

 attachment of ligamentous fibres, and occasionally presents a small facet for 

 articulation with the cuboid bone. 



To ascertain to which foot the bone belongs, hold it with the concave articular 

 surface backward, and the convex dorsal surface upward ; the external surface 

 i. e. the surface opposite the tubercle will point to the side to which the bone 

 belongs. 



Articulations. With four bones : astragalus and three cuneiform ; occasionally 

 also with the cuboid. 



Attachment of Muscles. Part of the Tibialis posticus. 



The Cuneiform Bones. 



The Cuneiform Bones have received their name from their wedge-like shape 

 (cuneus, a wedge ; forma, likeness). They form, with the cuboid, the anterior 

 row of the tarsus, being placed between the navicular behind, the three innermost 

 metatarsal bones in front, and the cuboid externally. They are called the frst, 

 second, and third, counting from the inner to the outer side of the foot, and, 

 from their position, internal, middle, and external. 



