Rannenivelä

Rannenivelä refers to the complex joint formed by the distal ends of the radius and ulna in the forearm and the carpal bones of the wrist. This articulation is crucial for a wide range of hand and wrist movements, including flexion, extension, abduction, adduction, pronation, and supination. It is comprised of the radiocarpal joint and the distal radioulnar joint.

The radiocarpal joint is a synovial joint where the concave articular surface of the distal radius and the articular disc of the distal radioulnar joint articulate with the convex surfaces of the scaphoid, lunate, and triquetrum bones of the proximal carpal row. This joint primarily facilitates the up-and-down and side-to-side movements of the hand.

The distal radioulnar joint is a pivot joint formed by the head of the ulna and the ulnar notch of the radius. It is enclosed by the articular disc of the distal radioulnar joint, which separates it from the radiocarpal joint. This joint is responsible for the rotation of the forearm, allowing the palm to face upwards (supination) or downwards (pronation).

The stability of the rannenivelä is maintained by a complex network of ligaments, including the volar and dorsal radiocarpal ligaments, the ulnar and radial collateral ligaments, and the triangular fibrocartilage complex (TFCC). The TFCC is a key structure that provides stability to both the radiocarpal and distal radioulnar joints. Injuries to the rannenivelä can result from trauma, repetitive strain, or underlying medical conditions, leading to pain, stiffness, and functional limitations.