Cuboid
Os cuboideum
Also known as: cuboid bone
A cube-shaped tarsal bone on the lateral side of the foot, between the calcaneus and the 4th and 5th metatarsals. It is the keystone of the lateral longitudinal arch.
Overview
The cuboid articulates posteriorly with the calcaneus (calcaneocuboid joint — the lateral half of the transverse tarsal joint), anteriorly with the bases of the 4th and 5th metatarsals, and medially with the lateral cuneiform (and sometimes the navicular). On its plantar surface the prominent cuboid tuberosity is bounded anteriorly by a deep groove for the tendon of fibularis longus, which turns around the lateral border of the foot here and crosses the sole to insert on the medial cuneiform and 1st metatarsal base; the long plantar ligament bridges the groove to form a tunnel. The short plantar ligament attaches behind the tuberosity.
- Location
Lateral midfoot, in front of the calcaneus.
Parts & subdivisions
- Converted into a tunnel by the long plantar ligament.
- Cuboid tuberosityPlantar prominence; attachment of long and short plantar ligaments.
Anatomy
- Articulations
Calcaneus, lateral cuneiform, navicular (occasionally), 4th and 5th metatarsals.
- Ossification
Usually a single centre just before or at birth (≈9 months fetal).
Function
- Keystone of the lateral longitudinal arch
- Pulley for the fibularis longus tendon
- Transmits load from the calcaneus to the lateral rays
Clinical significance
Nutcracker fracture
Compression fracture of the cuboid between the calcaneus and the 4th/5th metatarsal bases during forced abduction of the forefoot.
Cuboid syndrome
Subluxation of the cuboid in athletes and dancers causing lateral midfoot pain.
Compiled from standard anatomy and physiology references — see the Skeletal System sources. For education only; not medical advice.