Arches of the foot

The medial longitudinal arch is higher and more mobile: calcaneus, talus (keystone at its head), navicular, the three cuneiforms and metatarsals 1–3. Its pillars are the calcaneal tuberosity behind and the heads of metatarsals 1–3 in front. The lateral longitudinal arch is low and rests on the ground in standing: calcaneus, cuboid (keystone) and metatarsals 4–5. The transverse arch runs across the bases of the metatarsals, the cuneiforms and the cuboid; it is half a dome, completed by the opposite foot.

Support comes from (1) bone shape (wedge-shaped cuneiforms and metatarsal bases); (2) ligaments — the plantar calcaneonavicular (spring) ligament supporting the talar head, the long and short plantar ligaments and the plantar aponeurosis, which acts as a tie-beam (and, through the windlass mechanism, tightens when the toes dorsiflex at push-off, raising the arch); (3) muscles — tibialis posterior (most important dynamic support of the medial arch), fibularis longus and tibialis anterior (a stirrup under the midfoot), flexor hallucis longus and the intrinsic muscles.