The condition of bony or fibrous ankylosis of the phalangeal joint was designated “symphalangism” by Gushing in 1915. It is inherited as an autosomal dominant phenotype. It is usually bilateral. It is implied that the precartilaginous antagen of the consecutive phalanges of each digit are not separeted from one another in prenatal life. We reported 3 cases in a family with tarsal coalition, and discussed pathogenesis of the symphalangism.
