Capsule of the Carpometacarpal Joint, Anterior View

Description

Seen from the palmar (anterior) aspect, the fibrous capsule of the carpometacarpal joint spans the distal carpal row and the bases of the metacarpals, forming a continuous sleeve around the articular margins. The trapezium sits on the radial side articulating with the first metacarpal, while the trapezoid, capitate, and hamate align ulnarly with the second through fifth metacarpal bases. Articular cartilage caps the opposing surfaces, and the synovium would line the capsule deep to its fibrous layer. Palmar. Functionally, the anterior capsule and its thickened palmar carpometacarpal ligaments constrain translation at the relatively rigid index and middle rays while still permitting the cupping motion of the ulnar metacarpals and the large arc of the thumb CMC saddle joint. This is the joint complex examined when thumb basal joint osteoarthritis causes pain at the trapeziometacarpal articulation, and when subtle carpometacarpal fracture-dislocations of the ring and small finger metacarpals are missed on initial assessment. An anterior perspective also supports surgical orientation for approaches that work between thenar or hypothenar soft tissues to address CMC instability, arthrodesis, or trapeziectomy-based procedures. Use this illustration in gross anatomy and hand surgery teaching to clarify where the carpometacarpal capsule attaches relative to the distal carpal row, metacarpal bases, and the palmar joint line. It also fits well in orthopedic and radiology resources that correlate palmar-sided capsuloligamentous anatomy with CT or oblique hand radiographs in suspected CMC fracture-dislocation. Anatomical accuracy verified by SciePro's Medical Advisory Board.