The wrist is a complex joint that serves as the bridge connecting the forearm and the hand together.
It consists of a main radiocarpal joint, between the radius and the proximal row of the carpal bones minus the pisiform, and the smaller intercarpal joints, which are small joints among the carpals.
Then we have the hand, which consists of the carpo-metacarpal joints, the intermetacarpal joints, the metacarpophalangeal joints, and the interphalangeal joints.
Try saying those three times fast!!
Ok, let’s start with the wrist joint.
First, there’s the radiocarpal joint which is a condyloid type of synovial joint consisting of the distal radius and scaphoid, the lunate, and the triquetrum carpal bones.
Interestingly enough, the ulna doesn’t participate in the radiocarpal joint.
It is the articulating surface of the distal radius and the articular disc of the distal radio-ulnar joint which articulate with the proximal row of carpal bones to form the radiocarpal joint.
The articulating surfaces of the radiocarpal joint are surrounded by the tough joint capsule and synovial membrane, extending from the distal ends of the radius and ulna, to the scaphoid, the lunate, and the triquetrum.
The joint capsule of the radiocarpal joint is reinforced by a couple of ligaments, both on the dorsal and the palmar sides of the joint.
The palmar ligaments extend from the distal radius to the two rows of the carpal bones.
These ligaments strengthen the joint and make it possible for the hand and the radius to move as one unit during supination of the forearm, or turning the palm upwards.