Histologic anatomy of the triangular fibrocartilage.

Abstract

Histologic examination of the TFC reveals parallel, longitudinally oriented collagen fibers peripherally, while the more central articular disc is made up of interweaving obliquely oriented sheets of collagen fibers. This suggests a peripheral region experiencing tensile loads between the region of origin from the radius and the area of insertion into the ulna. The fiber orientation in the central region is more compatible with a structure experiencing multidirectional stresses. The articular disc origin from the radius is reinforced by collagen bundles projecting out from the radius for 1 to 2 mm. A large number of traumatic tears are oriented parallel to the radial origin of the TFC and located approximately 1 to 2 mm from the origin site. This corresponds to the junction of the short, radially oriented fibers and the remainder of the articular disc. The inner 80% of the articular disc is avascular, as is its radial attachment. Traumatic tears in this region would have a low healing potential unless some method for introducing additional vascularity was undertaken, such as reattachment through drill holes in the radius, allowing neovascularization of this otherwise avascular region.