Human body

Foot skeleton and arches

Anatomy · Foot biomechanics

How does a foot made of 26 small bones carry your whole weight with every step?

The bones of your foot form an arch, like a stone bridge, with the heel at one end and the ball of the foot at the other. When you stand the arch sags a few millimetres to soak up the shock, and when you push off it stiffens so the foot works like a firm lever.

The 26 bones of the foot form a sprung, arched structure that spreads body weight between the heel and the metatarsal heads, flattens slightly to absorb load and stiffens into a rigid lever for push-off. Bone shape, ligaments such as the spring ligament, muscles such as tibialis posterior and the plantar fascia — tightened by toe extension through the windlass mechanism — all hold the arch up.

Key facts

Bones per foot: 26 (7 tarsals, 5 metatarsals, 14 phalanges) + 2 hallux sesamoids
Arches: 3: medial longitudinal, lateral longitudinal, transverse
Navicular height (standing): ≈ 3.5–4.5 cm above the floor
Navicular drop, sitting → standing: ≈ 5–9 mm normal; > 10 mm suggests excessive pronation
Peak plantar fascia tension: ≈ 1 × body weight in late stance
Calcaneal pitch angle: ≈ 18–30° on a weight-bearing lateral radiograph

Parts you can explore (13)

Calcaneus
Talus
Navicular
Cuboid
Cuneiforms
Metatarsals
Phalanges
Tibia and fibula
Plantar fascia
Achilles tendon
Spring ligament
Tibialis posterior tendon
Medial longitudinal arch

In the 3D model

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