The windlass mechanism of the foot. A mechanical model to explain pathology.

This article presents a mechanical model that can be used to understand the foot, to help develop methods of treatment of foot pathology, and to provide direction for future research in foot mechanics and pathology. The anatomy and mechanical function of the windlass mechanism of the foot are analyzed using principles of mechanical engineering. The principles of force couples and free-body diagrams are explained and then applied to the foot. The relationship of the windlass mechanism to plantar fasciitis or heel spur syndrome, hallux abducto valgus, and hallux limitus is discussed.