The radioscapholunate ligament: a gross and histologic description.

The anatomic relationships of the carpal radioscapholunate ligament to its contiguous structures were analyzed by studying 1) 12 grossly dissected fresh adult wrists, and 2) multiple histologic sections from six adult wrists. Observations indicate that the radioscapholunate ligament originates from the prominence between the scaphoid and lunate articular facets on the distal articular surface of the radius, and from the palmar margin of the distal radius, deep and medial to the origin of the radiotriquetral and radiocapitate ligaments. The primary insertion of the radioscapholunate ligament is the medial margin of the proximal pole of the scaphoid. The ligament secondarily inserts into the lateral margin of the lunate and significantly contributes to the proximal portion of the scapholunate interosseous ligament. The radioscapholunate ligament is distinguished morphologically from the other palmar radiocarpal ligaments by its loosely organized collagen fibers and relatively high degree of vascularity. The radiotriquetral and radiocapitate ligaments are composed of densely fasciculated collagen fibers surrounded by perpendicularly oriented perifascicular and epiligamentous fibers. A fibrous capsular layer covers the most superficial aspect of each carpal ligament. On the deep surfaces of these ligaments, a condensation of epiligamentous fibers forms a synovial capsular layer. The palmar radiocarpal ligaments are truly intracapsular structures, as they are interposed between the fibrous and synovial capsular layers. No histologic evidence of elastin is present within the substance of these ligaments.