Dorsiflexion has been studied in three normal feet and in three feet with talipes equinovarus to determine the anatomical features which might contribute to the failure of operative treatment to correct the deformity. In the normal feet the movement of dorsiflexion was found to be essentially rotatory in nature and not simply hinging; as dorsiflexion proceeds the fibula moves forwards relative to the os calcis and the calcaneal tendon. In the club feet a posterolateral tether was found; this prevented fibular movement and blocked dorsiflexion. As a result of this study a posterior and lateral release is advocated for the operative correction of the hindfoot in a child with a club foot deformity, particularly under the age of a year.