radiocapitellar

Radiocapitellar refers to the radiocapitellar joint, the articulation between the head of the radius and the capitellum of the distal humerus. It is one component of the elbow joint, which also includes the humeroulnar joint and the proximal radioulnar joint. The radiocapitellar joint is a synovial articulation that contributes to elbow movement, with flexion and extension occurring primarily at the humeroulnar joint, while forearm rotation is largely governed by the proximal and distal radioulnar joints in conjunction with the interosseous membrane.

Anatomically, the radial head articulates with the capitellum and is covered by hyaline cartilage. The joint is enveloped by a relatively thin capsule and is reinforced laterally by the radial collateral ligament complex. The annular ligament surrounds the radial head, stabilizing it against the ulna during forearm rotation and elbow flexion.

Functionally, the radiocapitellar joint transmits axial loads from the forearm to the distal humerus and participates in smooth elbow motion. Overall elbow stability results from the capsule, ligaments, and surrounding muscles, with the radiocapitellar contact contributing to load sharing and joint congruity during movement.

Clinical significance and imaging emphasize radiocapitellar pathology and alignment. Radial head fractures can involve the radiocapitellar articulation, and radiographic assessment often uses the radiocapitellar line—an alignment line drawn through the centers of the radial head and capitellum on lateral elbow views—to evaluate elbow alignment after trauma. In pediatric injuries, radiocapitellar involvement is a consideration, and radial head subluxation with annular ligament injury (Nursemaid’s elbow) may affect the region.