The term "cavus foot" is used to describe a spectrum of foot shapes that have in common a high arch. The components of cavus are increased pitch and varus of the hindfoot, plantar flexion of the midfoot, and varus and adduction of the forefoot. The cavus shape is associated with changes in the mechanics of the foot. It is less flexible and balanced than a neutral foot. Although one fifth to one quarter of the population has a cavus foot, there is little anatomic description in the literature. This manuscript describes the anatomy and function of cavus foot.