Calcaneus

Calcaneus

Also known as: heel bone, os calcis, sustentaculum tali

The largest and strongest tarsal bone, forming the heel. It transmits body weight from the talus to the ground and is the lever for the calf muscles via the calcaneal (Achilles) tendon.

Overview

RankLargest tarsal bone

Böhler angle (normal)≈20–40°

The calcaneus is roughly rectangular. Its posterior surface bears the calcaneal tuberosity, whose middle part receives the calcaneal (Achilles) tendon (bursae lie in front of and behind it) and whose plantar part has medial and lateral processes — the weight-bearing heel and origins of abductor hallucis, flexor digitorum brevis, abductor digiti minimi and the plantar aponeurosis.

Its superior surface carries three facets for the talus (subtalar joint). The sustentaculum tali, a shelf projecting from the medial surface, supports the head/neck of the talus and has a groove on its undersurface for the flexor hallucis longus tendon; it anchors the spring and deltoid ligaments. The lateral surface carries the fibular (peroneal) trochlea separating the tendons of fibularis brevis (above) and longus (below). The anterior surface articulates with the cuboid (calcaneocuboid joint).

Location

Heel, below the talus.

Parts & subdivisions

Calcaneal tuberosity

Insertion of the calcaneal tendon; medial and lateral processes bear weight.

Sustentaculum tali

Medial shelf supporting the talus; groove for flexor hallucis longus.

Fibular trochlea

Separates fibularis brevis and longus tendons.

Talar facets

Posterior, middle and anterior facets of the subtalar joint.

Cuboid articular surface

Calcaneocuboid joint (part of the transverse tarsal joint).

Anatomy

Articulations

Talus (subtalar and talocalcaneonavicular joints), cuboid (calcaneocuboid joint).

Ligaments

Interosseous talocalcaneal, calcaneofibular, plantar calcaneonavicular (spring), long and short plantar ligaments, bifurcate ligament.

Ossification

Primary centre ≈month 3 fetal (first tarsal to ossify); secondary centre for the posterior tuberosity ≈6–8 years, fusing ≈14–16 years.

Clinical significance

Calcaneal fracture

The commonest tarsal fracture, from axial loading (fall from a height onto the heels); often intra-articular with flattening of the Böhler angle (< 20°). ≈10% have an associated lumbar spine (burst) fracture and many are bilateral — always examine the spine and other heel.

Plantar fasciitis and Sever disease

Heel pain at the medial calcaneal tubercle origin of the plantar fascia (worst with the first steps in the morning); in active children, traction apophysitis of the calcaneal tuberosity (Sever disease).