Cuboid
Os Cuboideum
location_on Lateral midfoot, between the calcaneus and the 4th and 5th metatarsals
The cuboid is a cube-shaped bone on the lateral side of the foot that serves as the keystone of the lateral longitudinal arch. It articulates posteriorly with the calcaneus, anteriorly with the fourth and fifth metatarsals, and medially with the lateral cuneiform. The plantar surface has a prominent groove (sulcus) through which the peroneus longus tendon passes before inserting on the medial side of the foot.
Key Anatomical Features
- Plantar groove (sulcus) channels the peroneus longus tendon across the sole of the foot
- Calcaneal process (tuberosity) on the plantar surface is a lateral arch support point
- Proximal surface is concavoconvex for articulation with the calcaneus
- Distal surface has two facets for the fourth and fifth metatarsal bases
- Keystone of the lateral longitudinal arch of the foot
Muscle Attachments
| Muscle | Attachment | Action |
|---|---|---|
| Peroneus longus tendon | Passes through the cuboid groove en route to the medial cuneiform and first metatarsal | Everts the foot and plantarflexes the ankle |
| Tibialis posterior (slip) | May send a tendinous slip to the cuboid | Supports the foot arches |
| Flexor hallucis brevis | Plantar surface of cuboid (partial origin) | Flexes the proximal phalanx of the great toe |
| Adductor hallucis (oblique head) | Plantar surface of cuboid (partial origin) | Adducts the great toe |
Joints and Articulations
| Joint | Type | Connects to |
|---|---|---|
| Calcaneocuboid joint | Synovial saddle (part of transverse tarsal joint) | Calcaneus |
| Fourth tarsometatarsal joint | Synovial plane | Fourth metatarsal |
| Fifth tarsometatarsal joint | Synovial plane | Fifth metatarsal |
Common Pathologies
Cuboid fracture
Uncommon but can occur from direct trauma or as a nutcracker fracture, where the cuboid is compressed between the calcaneus and metatarsal bases during forced abduction of the forefoot.
Cuboid syndrome
Subtle subluxation of the calcaneocuboid joint or peroneus longus dysfunction causing lateral midfoot pain, often in dancers and athletes. Treated with cuboid manipulation (whip technique).
Lisfranc injury (involvement)
The cuboid may be involved in tarsometatarsal joint complex injuries, particularly in the lateral column.
Clinical Relevance
Cuboid fractures are frequently missed on initial radiographs and may require CT scanning. Nutcracker fractures occur with calcaneal fractures or midfoot abduction injuries. Cuboid syndrome is a clinical diagnosis often missed in patients with lateral foot pain, but it can be successfully treated with the cuboid whip manipulation technique. The calcaneocuboid joint is part of the Chopart (transverse tarsal) joint, which is critical for foot flexibility.
Development and Ossification
The cuboid ossifies from a single center that appears around the time of birth (36th-40th fetal week), making it the first tarsal bone to ossify after the calcaneus and talus. Its presence at birth is used as an indicator of gestational maturity.
Did You Know?
- Cuboid literally means cube-shaped in Greek (kuboeides), though it is not a perfect cube
- The peroneus longus tendon travels through a groove in the cuboid, one of the few places a tendon passes through a groove in a bone in the foot
- The cuboid's presence at birth (visible on X-ray) helps confirm a full-term delivery in neonatal medicine
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