Cadaveric and fresh amputation dissection studies revealed that condylar anomalies, metatarsal axial rotation, and bowstrung flexor tendos will commonly produce subluxation and degenerative changes at the metatarsophalangeal-sesamoid joint. The average arc of motion of the sesamoids from maximum plantar- and dorsiflexion was measured at 71.9 +/- 11 degrees. The anatomic variations presented are correlated with the incidence of chronic sesamoiditis, painful bipartite sesamoids, and chronic nonunions.