Midcarpal joint
From Ganfyd
The midcarpal joint is the joint between the proximal row and distal row of carpal bones. It is a compound joint, with medial and lateral compartments. It is also a synovial joint.
Note that the midcarpal joint is not strictly a single joint anatomically; however, the various articulations between the two rows of carpal bones function as a single unit.
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Structure
The medial compartment consists of the articulation between the distal surfaces of triquetral, lunate and scaphoid and the proximal surfaces of hamate and capitate. The distal surface is largely convex, the proximal surface concave, except for the most medial part in which the opposite is true, giving a sellar shape.
The lateral compartment is formed by the articulation of the trapezium and trapezoid with the scaphoid.
A fibrous capsule encloses the joints of the carpus, with a synovial membrane lining this capsule, attaches to the margins of the articular surface of each carpal bone.
Movements
See wrist (region)
There are two types of joint system within the midcarpus: the uniaxial joint of scaphoid and distal row, and the biaxial joint between lunate, triquetrum and distal row. The intercarpal joints of the proximal row accommodate these movements and allow the joint surfaces to stay congruent[1].
Ligaments
Four ligaments stabilise the midcarpal joint:
- A dorsal ligament
- A palmar ligament
- A radial ligament
- An ulnar ligament.
