Radiate carpal ligament
Ligamentum radiatum carpi
A star of short fibrous bands on the palmar face of the carpus, fanning out from the capitate to the surrounding carpal bones.
At a glance
- English
- Radiate carpal ligament
- Latin (TA2)
- Ligamentum radiatum carpi
- System
- Ligament
- Region
- Hand
- Side
- Paired, left and right
About the radiate carpal ligament
On the palmar side of the wrist, deep to the flexor tendons, the carpal bones are tied together by a set of short ligaments. The radiate carpal ligament is the part of this system centred on the head of the capitate, the largest carpal bone. From the capitate its bands spread out like the spokes of a wheel, which gives the ligament its name.
Most of the bands pass upwards and outwards to the bones of the proximal row: the scaphoid on the lateral side, the lunate in the middle and the triquetrum medially. Smaller slips run sideways to the neighbouring bones of the distal row. The ligament therefore spans the palmar aspect of the midcarpal joint, the S-shaped joint line between the proximal and distal rows.
The capitate is the keystone of the carpus and moves with the third metacarpal as a single unit. By binding the capitate to the proximal row, the radiate fibres help to keep the two rows in register as the wrist bends, straightens and deviates. Together with the other palmar intercarpal ligaments they also make up much of the floor of the carpal tunnel, over which the long flexor tendons and the median nerve run.
These bands are rarely injured on their own. They become relevant in high-energy wrist injuries such as perilunate dislocations, in which the capitate is driven away from the lunate and the palmar ligaments around the head of the capitate are torn. Loss of this support contributes to midcarpal instability, in which the wrist clunks as it moves from radial to ulnar deviation.
Attachments and function
- Attaches from
- The palmar surface of the head and neck of the capitate.
- Attaches to
- The palmar surfaces of the scaphoid, lunate and triquetrum, with small slips to the adjacent bones of the distal row.
- Function
- Binds the capitate to the proximal carpal row, steadies the midcarpal joint and helps form the floor of the carpal tunnel.
Anthromica
See the radiate carpal ligament where it really sits, with every layer of the body around it.
- Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
- English and Latin. Every structure named the way your exam names it.
- Quiz until it sticks. Short drills on the structures you keep missing.
Free to start. No card.
