Anatomy of the collateral ligaments of the proximal interphalangeal joint.

Abstract

To study and clarify the anatomy of the proper collateral ligaments and accessory collateral ligaments of the proximal interphalangeal joint. The collateral ligaments of 8 proximal interphalangeal joints were dissected under an operating microscope to gain an appreciation of their fiber direction and the anatomy of their origin and insertion. Two undissected joints were studied histologically. The proper collateral ligament was found to arise widely from dorsal and proximal to and from the fovea on the side of the head of the proximal phalanx and insert for some distance on most of the side of the base of the middle phalanx. The ligament is stout and its fibers are oriented parallel to the middle phalanx in all positions of the joint. The accessory collateral ligament was found to be a less substantial structure lying between the proper collateral ligament and the volar plate. The anatomy shown by this study is quite different from that shown in most of the anatomic and hand surgery literature, particularly in line drawings.