Cuboid bone
Os cuboideum
The cuboid is a roughly cube-shaped tarsal bone on the outer side of the midfoot. It sits between the heel bone and the fourth and fifth metatarsals.
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Free 3D model of the cuboid bone. Right foot. Drag to rotate, zoom with + and − (or Ctrl + scroll), click a bone to highlight and name it.
Key points
- The cuboid is the tarsal bone on the outer side of the midfoot.
- It sits between the heel bone and the fourth and fifth metatarsals.
- A groove on its underside guides a tendon across the sole.
- It is the main bone of the outer arch.
What is the cuboid bone?
The cuboid is a roughly cube-shaped tarsal bone on the outer side of the foot. It is the only midfoot bone in the outer column.
Where is the cuboid bone?
It lies on the outer edge of the foot, about halfway between the heel and the little toe.
To find it, feel for the bump at the base of the fifth metatarsal, halfway along the outer border. The cuboid is the bone just behind that bump.
What does the cuboid articulate with?
Behind, it meets the calcaneus. In front, it carries the bases of the fourth and fifth metatarsals. On its inner side it rests against the lateral cuneiform and sometimes the navicular.
The groove on the cuboid
A groove runs across the underside of the cuboid. The tendon of fibularis longus turns under the foot in this groove on its way to the base of the first metatarsal.
The cuboid works as a pulley for that tendon. Some people have a small sesamoid bone, the os peroneum, in the tendon where it bends around the cuboid.
What does the cuboid do?
It is the keystone of the outer arch. It links the heel bone to the outer two metatarsals and keeps the outer border of the foot stable while still allowing it some give.
Common problems with the cuboid
The cuboid is seldom broken on its own. It can be crushed between the heel bone and the metatarsals when the forefoot is forced outward.
Pain on the outer side of the midfoot after an ankle sprain is sometimes put down to a small shift of the cuboid. This page describes anatomy only.
Common questions
Where is the cuboid bone?
On the outer edge of the midfoot, just behind the base of the fifth metatarsal.
What does the cuboid articulate with?
The calcaneus, the fourth and fifth metatarsals and the lateral cuneiform.
Why is it called the cuboid?
Because it is roughly cube-shaped.
Is the cuboid a tarsal bone?
Yes. It is one of the seven tarsals.
Is this 3D model of the cuboid bone free?
Yes. The interactive 3D model on this page is free to view and use for study, with no account or download needed. Its geometry comes from the open BodyParts3D data set (CC BY-SA).
About this free 3D model of the cuboid bone
The interactive 3D model on this page is free to use in your browser, with no sign-up. It is built from scan-based anatomy data, so every bone is a separate, correctly placed shape you can turn and inspect from any side.