Joint · Hand

Wrist joint

Articulatio radiocarpalis

Where the forearm meets the hand. The lower end of the radius articulates with the first row of carpal bones — the scaphoid and lunate — in an egg-in-socket arrangement that allows bending in two planes but no true rotation. The ulna does not reach the wrist directly: a fibrocartilage disc sits in the way. What we casually call wrist movement is really shared between this joint and the row of joints just beyond it, which is why the wrist keeps working reasonably well even when one part of it is stiff.