Pes Cavus, known also as a high instep or supinated foot, is a foot condition classified by an arch that does not fall flat upon bearing weight. In Latin, pes cavus stands for "hollow foot". It is medically described as a multi-planar foot deformity most recognized by the presence of a noticeably high arch. Pes Cavus is known to occur in approximately 8-15% of the population, however, it is far less recognized than its counterpart, Pes Planus.
Pes Cavus is typically a result of a fixed plantar flexion of the foot. Plantar Flexion is the movement of the ankle, pointing the toes away from the shin (think pressing a gas pedal in your car). However, a fixed plantar flexion does not guarantee that a person has pes cavus.