Carpometacarpal joints

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The carpometacarpal joints (CMC joints) are plane synovial joints between the four metacarpal bones of the fingers and the distal row of carpal bones. The joints are largely structural, their movements restricted to gliding motions between the adjacent bones. There

The carpometacarpal joint of the thumb is very different from the other carpometacarpal joints, having a wide range of movement and very different structure.



The index carpometacarpal joint occurs between the trapezium, trapezoid and the index metacarpal.

The middle carpometacarpal joint occurs between the capitate and the middle metacarpal.

The ring carpometacarpal joint occurs between the capitate, hamate and ring metacarpal.

The little carpometacarpal joint occurs between the hamate and little metacarpal.


The amount of gliding permitted at each carpometacarpal joint varies. The index and middle carpometacarpal joints are almost immobile; there is a small degree of movement at the ring carpometacarpal joint; and the little carpometacarpal joint has the greatest degree of movement, to assist in opposition of that digit.


  • Dorsal ligament
  • Palmar ligament
  • Interosseous ligament (usually only middle and ring carpometacarpal joints display these)

See Also