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Carpal and metacarpal joint type???

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Joint types of the wrist/hand articulations:
Intercarpal joints (between the carpal bones themselves, both proximal row and midcarpal joint)
  • Type: Synovial plane (gliding) joint
  • Flat/slightly curved articular surfaces that let the carpal bones glide on each other, contributing mainly to positioning of the hand during wrist flexion, extension, and radial/ulnar deviation (Gray's Anatomy for Students, p. 2892-2894; Imaging Anatomy Text and Atlas Vol. 3, p. 756-762)
Carpometacarpal (CMC) joints - these are not all the same type:
  • 1st CMC joint (thumb, trapezium-1st metacarpal): Saddle (sellar) joint - biaxial, with reciprocally concave-convex articular surfaces, giving the thumb its wide range of movement (flexion/extension, abduction/adduction, and opposition/circumduction) needed for pinch and grasp - Imaging Anatomy Text and Atlas Vol. 3, p. 763; also confirmed in Campbell's Operative Orthopaedics ("the saddlelike first carpometacarpal joint provides the circumductive movement of the thumb")
  • 2nd-5th CMC joints (index through little finger): Plane (gliding) synovial joints, functionally part of the same synovial complex as the intercarpal joints - allowing only limited gliding/sliding movement
Summary table:
JointTypeMovement
Intercarpal jointsPlane (gliding) synovialLimited gliding
2nd-5th CMC jointsPlane (gliding) synovialLimited gliding
1st CMC joint (thumb)Saddle (sellar) synovialBiaxial - flexion/extension, abduction/adduction, opposition
The thumb CMC joint is the exception to remember - it's the only saddle joint in the hand, which is why the thumb has such unique mobility compared to the other digits.
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