Cuboid bone: the lateral tarsal bone of the midfoot

What it is

A cube-shaped tarsal bone on the lateral side of the foot.

Location

Lies in front of the calcaneus, with the lateral cuneiform medially and the fourth and fifth metatarsals in front.

Function

Supports the lateral longitudinal arch and gives a groove for the tendon of fibularis longus.

Body system

Skeletal · paired (left and right)

FMA ID

FMA24529 (Foundational Model of Anatomy)

Key facts

• A deep groove on its plantar surface carries the tendon of fibularis longus toward the medial side of the foot.
• Its joint with the calcaneus (calcaneocuboid joint) and the talonavicular joint together form the transverse tarsal (Chopart) joint.
• It articulates with the calcaneus, lateral cuneiform, fourth and fifth metatarsals, and sometimes the navicular; the long plantar ligament attaches to its plantar ridge.

Clinical relevance

Forced abduction of the forefoot can crush it between the calcaneus and the fourth and fifth metatarsals (nutcracker fracture).

The cuboid is the most lateral bone in the distal row of tarsal bones. It lies proximal to the fourth and fifth metatarsals, distal to the calcaneus and lateral to the navicular and the cuneiform bones. Anatomists group it with the navicular and three cuneiforms as the bones of the midfoot, while the talus and calcaneus make up the hindfoot. (Kenhub: Tarsal bones.)

The bases of the metatarsals articulate with the cuboid or the cuneiforms. The base of the fifth metatarsal has a lateral expansion that forms a bump you can feel on the outer border of the foot; the cuboid lies just behind it. (OpenStax Anatomy and Physiology 2e, 8.4: Bones of the Lower Limb.)

The cuboid has five articular surfaces: in front for the bases of the fourth and fifth metatarsals, behind for the calcaneus, and on its medial side for the lateral cuneiform and the navicular. (Angoules et al. Update on diagnosis and management of cuboid fractures. World J Orthop 2019.)

Its inferior (plantar) surface carries a deep groove for a muscle tendon. That tendon is fibularis (peroneus) longus, which runs down behind the lateral malleolus and then crosses under the foot to insert on the medial cuneiform and the base of the first metatarsal. (TeachMeAnatomy: Muscles in the Lateral Compartment of the Leg.)

The groove guides the fibularis longus tendon and acts as a fulcrum, a pulley around which the muscle pulls. Repeated pull of the tendon through this groove has been proposed as one cause of cuboid stress fractures. (Angoules et al. Update on diagnosis and management of cuboid fractures. World J Orthop 2019.)

The lateral head of flexor hallucis brevis, a short muscle of the big toe, arises from the plantar surfaces of the cuboid and lateral cuneiform and inserts on the base of the proximal phalanx of the great toe. (TeachMeAnatomy: The Muscles of the Foot.)

The cuboid takes part in the calcaneocuboid, cuboideonavicular, cuneocuboid and tarsometatarsal joints. Its tarsometatarsal joints are with the bases of the fourth and fifth metatarsals. (Kenhub: Tarsal bones.)

The calcaneocuboid joint is a saddle-shaped synovial joint with its own capsule. Together with the talonavicular joint it makes up the transverse tarsal joint (midtarsal or Chopart's joint), a functional unit that allows pronation and supination of the foot. The calcaneocuboid joint is supported by the calcaneocuboid part of the bifurcate ligament, the dorsal calcaneocuboid ligament, the long plantar ligament and the plantar calcaneocuboid (short plantar) ligament. It is innervated by the deep fibular, sural and lateral plantar nerves and supplied by the lateral tarsal artery, a branch of the dorsalis pedis artery. (Kenhub: Transverse tarsal joint.)

The cuboid is the only bone of the tarsus involved both in the tarsometatarsal (Lisfranc) joint complex and in the midtarsal (Chopart) joint. The fourth and fifth tarsometatarsal joints it forms are about three times as mobile as the first to third, and contribute most of the dorsiflexion and plantarflexion that happens in the midfoot. (Angoules et al. Update on diagnosis and management of cuboid fractures. World J Orthop 2019.)

The lateral longitudinal arch is made of the calcaneus, the cuboid and the fourth and fifth metatarsals. It is flatter than the medial arch and lies on the ground when standing. The cuboid also forms part of the transverse arch, together with the metatarsal bases and the three cuneiforms. (TeachMeAnatomy: The Arches of the Foot.)

Unlike the navicular and cuneiforms, the cuboid contributes only to the lateral longitudinal arch, not the medial one. The fibularis longus tendon, which wraps under the cuboid, is the main contributor to stability of the lateral arch and also maintains the curve of the transverse arch, assisted by tibialis posterior. (Kenhub: Arches of the foot.)

In surgical terms the cuboid is the main supporting element of the rigid lateral column of the foot, helping to keep that column at the right length, and it links the lateral column to the transverse arch. (Angoules et al. Update on diagnosis and management of cuboid fractures. World J Orthop 2019.)

Each tarsal bone ossifies from its own centre at a different time. In the classic Keibel and Mall table, the calcaneus and talus begin in the sixth fetal month, the cuboid at about birth, the lateral cuneiform in the first year, the medial cuneiform in the second to third year, the intermediate cuneiform in the third to fourth year and the navicular in the fourth to fifth year. (UNSW Embryology: Lower limb ossification table.)

Isolated cuboid fractures are rare, with a reported annual incidence of about 1.8 per 100,000 people in the United Kingdom. Most occur together with other midfoot fractures or with Lisfranc and Chopart injuries, from crushing forces or avulsion of ligament attachments, such as the calcaneocuboid ligament in an inversion sprain. (Angoules et al. Update on diagnosis and management of cuboid fractures. World J Orthop 2019.)

A nutcracker fracture is a compression fracture of the cuboid squeezed between the calcaneus and the bases of the fourth and fifth metatarsals, first described by Hermel and Gershon-Cohen in 1953. It results from forced plantarflexion of the hindfoot and midfoot against a fixed, abducted forefoot and has also been reported in children after horse-riding injuries. Stress fractures of the cuboid are less common than those of the calcaneus or navicular. (Angoules et al. Update on diagnosis and management of cuboid fractures. World J Orthop 2019.)

Cuboid syndrome is lateral foot pain caused by altered congruity of the calcaneocuboid joint and subluxation of the cuboid. It usually affects athletes and dancers and gives pain on the plantar side of the cuboid. Two clinical tests are described for it, the midtarsal adduction test and the midtarsal supination test. (Angoules et al. Update on diagnosis and management of cuboid fractures. World J Orthop 2019.)

The navicular is the boat-shaped bone on the medial side of the midfoot, between the talus behind and the three cuneiforms in front. The cuneiforms (medial, intermediate and lateral) are wedge-shaped and sit in front of the navicular, articulating with the metatarsals in front of them. The cuboid is the lateral partner of this group: it sits beside the navicular and lateral cuneiform and carries the fourth and fifth metatarsals. (TeachMeAnatomy: Bones of the Foot: Tarsals, Metatarsals and Phalanges.)

In OpenStax's summary, the navicular articulates with the talus, the three cuneiforms and the cuboid, and the cuboid articulates with the calcaneus, the navicular and the lateral cuneiform. (OpenStax Anatomy and Physiology 2e, 8.4: Bones of the Lower Limb.)

The nearest named structures in the 3D model, measured from the centre of each part:

• Lateral cuneiform bone · skeletal
• Lateral plantar artery · cardiovascular
• Long plantar ligament · skeletal
• Lateral tarsal artery · cardiovascular
• Plantar arch · cardiovascular
• Dorsal venous arch of foot · cardiovascular
• Plantar venous arch of foot · cardiovascular
• Intermediate cuneiform bone · skeletal
• Abductor digiti minimi of foot · muscular
• Flexor accessorius · muscular