Os intermetatarseum and a possible relationship to hallux valgus.

The accessory bones of the foot have fascinated anatomists for five centuries. Andreas Vesalius in I 568 (published in I 725) was the first to draw attention to an accessory ossicle situated at the base of the fifth metatarsal bone, and much has been written subsequently about two distinct groups of accessory bones. In the first are those which are contained within the fibres of tendons and are true sesamoid bones. In the second ossicles are A found lying in the tarsus and the forefoot which are of embryological interest only and which do not as a rule contribute to the mechanics of the foot (O’Rahilly 1953). The os intermetatarseum, a rare accessory bone of the forefoot, is occasionally found lying between the bases of the first and second metatarsal bones. It was first described by Gruber ( I 856). It was also noted by several anatomists of the nineteenth century in their dissections of anatomical specimens. Pfitzner (I 896) gave the first detailed account of the ossicle (Fig. I ) and, after his work was published, it was rediscovered at least three times in the ----------early part ofthis century. Shands (1931) in a . FIG. I