Refractory flatfoot, particularly in children before the age of 8 or 9 years, is sometimes due to a supernumerary bone. Some of these bones undoubtedly cause symptoms of, or predispose to, flatfoot. In some hypertrophic arthritis develops in the true joint space. Surgical removal is thus often indicated.1
When the roentgenogram of the navicular bone shows an unusual condition, one should consider the possibility of a developmental variation.2 That such an anomaly is by no means a rare occurrence was pointed out by Schindler and Gnagi.3 In their experience, they found an 8 per cent occurrence of painful, divided navicular bone of the foot. The smooth contour and linear margin of density on the opposing surfaces eliminate the diagnosis of fracture of the navicular bone. Divided navicular bone is a bilaterally occurring anomaly. It develops as an ossification center of the navicular bone, which, instead of uniting