has part has part characteristic of has modifier Rocker bottom foot Congenital vertical talus is characterized by pes valgus, a rigid flatfoot deformity (as opposed to a flexible calcaneovalgus foot) caused by a malpositioned navicular bone at the neck of the talus; the ankle is in severe equinus and the forefoot in dorsiflexion, rocker bottom-like, accompanied by contraction of the talonavicular, deltoid and calcaneal cuboidal ligaments. The foot examination usually reveals a rigid foot with a "reversed" arch, a convex plantar surface, and a deep crease on the lateral dorsal side of the foot. The ankle joint is plantarflexed, while the midfoot and forefoot are extended upward. Lateral foot radiographs are helpful in confirming the diagnosis. Abnormal talus morphology abnormal vertical talus