The term cavus refers to an increased concavity or hollowness of the plantar longitudinal arch and the transverse arch located in the tarsometatarsal region, as well as under the metatarsal heads. In this chapter,
transverse cavus relates to the tarsometatarsal region,
longitudinal cavus can refer to the whole arch or its medial or lateral margins, while the term
forefoot cavus describes a particular configuration of the metatarsal heads (cf. Chap. 9). Cavus may be accompanied by a coronal (transverse) imbalance of the foot into
valgus or
varus. Many structural combinations occur, and the etiology is diverse. The following broad classification is convenient for descriptive purposes both from the point of view of origin and treatment:
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Physiological pes cavus
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Idiopathic acquired pes cavus in infancy or adulthood
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Neurological pes cavus due to hypertonia or spasticity
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Pes equinocavus in specific neurological conditions
