Tarsal bones
Ossa tarsi
Also known as: tarsus, ankle bones
Seven short bones forming the posterior half of the foot: talus, calcaneus, navicular, cuboid and three cuneiforms. They transmit body weight from the leg to the ground and form the posterior arches of the foot.
Overview
The tarsus is arranged in a proximal group — the talus (articulating with the leg bones) sitting on the calcaneus (heel) — an intermediate bone, the navicular, on the medial side, and a distal row of the medial, intermediate and lateral cuneiforms and the cuboid articulating with the metatarsals. The medial column (talus, navicular, cuneiforms, metatarsals 1–3) forms the high medial longitudinal arch; the lateral column (calcaneus, cuboid, metatarsals 4–5) the low lateral longitudinal arch.
Key joints: the subtalar (talocalcaneal) joint and the transverse tarsal (midtarsal, Chopart) joint — talonavicular plus calcaneocuboid — allow inversion and eversion; the tarsometatarsal (Lisfranc) joints form the boundary with the forefoot. Body weight is transmitted from the tibia to the talus and then backward to the calcaneal tuberosity and forward along the arches to the metatarsal heads.
Ossification: only the calcaneus, talus and usually the cuboid are ossified at birth; the lateral cuneiform appears ≈1 year, the medial cuneiform ≈2 years, the intermediate cuneiform ≈3 years and the navicular last (≈3–4 years).
- Location
Hindfoot and midfoot, between the leg bones and the metatarsals.
Parts & subdivisions
- Links leg and foot; no muscle attachments.
- Heel bone; largest tarsal.
- Boat-shaped; between talus and cuneiforms.
- Lateral; groove for fibularis longus.
- Articulate with metatarsals 1–3.
Anatomy
- Articulations
Ankle (talocrural), subtalar, transverse tarsal (Chopart), intertarsal, tarsometatarsal (Lisfranc) joints.
Function
- Transmit and distribute body weight to the heel and forefoot
- Form the hindfoot and midfoot arches
- Allow inversion and eversion of the foot
- Provide a rigid lever for push-off and a flexible adapter on uneven ground
Clinical significance
Lisfranc injury
Disruption of the tarsometatarsal joint complex (often the Lisfranc ligament from the medial cuneiform to the base of the 2nd metatarsal) from a twisting fall on a plantarflexed foot; plantar ecchymosis and widening between the 1st and 2nd metatarsal bases — easily missed.
Tarsal coalition
Congenital fibrous, cartilaginous or bony union (calcaneonavicular or talocalcaneal) causing a rigid, painful flatfoot in adolescents.
Mnemonics
Tarsal bones
"Tiger Cubs Need MILC" — Talus, Calcaneus, Navicular, Medial, Intermediate, Lateral cuneiforms, Cuboid.
Compiled from standard anatomy and physiology references — see the Skeletal System sources. For education only; not medical advice.