THE METATARSAL BONES 83 



The anterior surface is smooth. In the transverse direction it is 

 markedly convex, and blends with the lateral surfaces, which are likewise 

 convex and rounded. On the outer surface is a groove, which commences 

 at the upper extremity of the bone, and which runs obliquely downwards 

 and backwards to the channel formed anteriorly between the external 

 small and the large metatarsal bones. This groove is for the accommo- 

 dation of the large metatarsal artery. A much fainter vascular imprint 

 is left on the inner aspect of the bone near its upper extremity by the 

 internal metatarsal vein. 



The posterior surface is comparatively flat. This surface presents on 

 either side a roughened triangular area, the apex of which is directed 

 downwards. To these areas the small metatarsal bones are articulated. 

 They are placed in the upper two-thirds of the bone. In its lower 

 third the posterior surface is smooth, as is also the area between the two 

 small bones. The nutrient foramen is found on the line of division 

 between the upper and middle thirds of this surface. Occasionally two 

 such foramina are present. 



The upper surface of the superior extremity articulates with the 

 lower row of tarsal bones. On this surface two small facets are pre- 

 sented outwardly for articulation with the cuboid. Between these 

 facets there is an area which is roughened and non-articular, and 

 which extends inwardly to the middle of the surface. The main 

 portion of the upper surface is articulated to the large cuneiform 

 bone, but a single small facet is found postero-internally, which articu- 

 lates with the cuneiform parvum. Anteriorly the upper extremity 

 presents towards its inner side a roughened elevation, to which the 

 tendon of insertion of the flexor metatarsi muscle is attached, whilst 

 at the back of this extremity we find on either side two small facets, 

 which articulate with like facets on the heads of the small metatarsal 

 bones. 



The inferior extremity of the bone is very similar to that of the 

 large metacarpal, and presents an antero-posterior articular ridge separat- 



