Abstract
1. The pedigree of a family in which lobster claw foot and triphalangeal thumb occurred together is presented. The affected members of two generations are described. The clinical appearances and radiological abnormalities are described in detail. Results of surgical treatment of the forefoot cleft are presented.
2. Lobster clawing of the foot is discussed with particular reference to associated hand and finger abnormalities. Triphalangeal thumb is discussed. The current and probably acceptable theory of the etiology of duplication is expanded. A hypothesis is formulated of excessive activity at the pre-and post-axial borders of the distal limb bud, followed by variable resorption, to explain not only the cause of lobster claw foot but also its occurrence in association with triphalangeal thumb.
