Capitate bone
Os capitatum
The capitate is the largest of the eight carpal bones. It sits in the centre of the wrist, in line with the middle finger, and its rounded head fits into the hollow of the lunate and scaphoid.
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Free 3D model of the capitate bone. Right hand. Drag to rotate, zoom with + and − (or Ctrl + scroll), click a bone to highlight and name it.
Key points
- The capitate is the largest carpal bone and lies in the centre of the wrist.
- It has a rounded head that fits into the lunate and scaphoid.
- It joins seven bones, more than any other carpal.
- It carries the third metacarpal and forms the central pillar of the hand.
What is the capitate bone?
The capitate is the largest of the eight carpal bones. Its name comes from the Latin caput, a head, because the end facing the forearm is rounded like a small head.
It belongs to the distal row, the row next to the palm, and sits in the middle of it. The other carpals are arranged around it, and the wrist turns about a point inside its head.
Where is the capitate bone?
It lies in the centre of the wrist, in line with the middle finger. The lunate is behind it, the third metacarpal is in front of it, the trapezoid is on its thumb side and the hamate is on its little finger side.
To find it, follow the long bone of your middle finger down the back of the hand to its base. Just beyond the base there is a small hollow. The capitate lies under this hollow, and it fills out when the wrist is bent forward.
What does the capitate look like?
The capitate has three parts. The head is the rounded end facing the forearm. Below it is a slightly narrowed neck. The body is the broad, block-like part that faces the metacarpals.
The head and the sides are smooth and covered with cartilage. The palm and back surfaces are rough for ligaments and for one muscle of the thumb.
What does the capitate articulate with?
The capitate touches seven bones, more than any other carpal. Its head sits in a socket formed by the lunate and the scaphoid. This ball-in-socket arrangement is the centre of the midcarpal joint.
On its sides it meets the trapezoid and the hamate. In front, its body meets the base of the third metacarpal, and by smaller facets the second and fourth metacarpals.
What attaches to the capitate?
Many ligaments spread out from the palm surface of the capitate to the bones around it. Because of this fan shape, they are together called the radiate carpal ligament.
One muscle starts partly from the capitate. The oblique head of adductor pollicis, which pulls the thumb towards the palm, arises from it and from the bases of the nearby metacarpals.
What does the capitate do?
The capitate is the keystone of the wrist. It sits at the top of the arch formed by the carpal bones and locks the distal row together.
It is also the main path for force. Load from the middle finger and the palm runs through the third metacarpal into the capitate, then through the lunate and scaphoid to the radius. The axes about which the wrist bends and tilts both pass through its head.
Common problems with the capitate
The capitate is well protected in the centre of the wrist, so fractures are uncommon. When they occur they usually cross the neck, and often accompany a scaphoid fracture after a heavy fall on the hand.
Like the scaphoid, the head of the capitate receives its blood from vessels that enter further down the bone. A break at the neck can therefore heal slowly. This page describes anatomy only.
Common questions
Is the capitate the largest carpal bone?
Yes. It is the largest of the eight.
Which finger lines up with the capitate?
The middle finger. The capitate carries the third metacarpal.
How many bones touch the capitate?
Seven: the scaphoid, lunate, trapezoid, hamate and the second, third and fourth metacarpals.
Which carpal bone forms first?
The capitate is usually the first carpal to begin turning from cartilage to bone, in the first months of life.
Is this 3D model of the capitate 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 capitate 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.