The intrinsic and extrinsic ligaments of the wrist. A correlation of collagen typing and histologic appearance.

20 fresh frozen human wrist specimens were dissected. Gross and histological examination and biochemical evaluation were performed on the intrinsic ligaments (scapho-lunate and luno-triquetral) and extrinsic ligaments (radio-scapho-capitate and radio-lunate). All ligaments were observed to have longitudinal collagen bundles. The intrinsic ligaments had large amounts of fibrocartilage near insertions and no elastin, while the extrinsic ligaments had little fibrocartilage and sparse amounts of elastin. The intrinsic ligaments were noted to have significantly more collagen Type 3 (41%) than the extrinsic ligaments (19%). These findings suggest that structural differences between the intrinsic and extrinsic ligaments of the wrist may in part account for the biomechanical observations that the intrinsic ligaments are stronger and elongate further prior to failure than the extrinsic ligaments.