A method for evaluating carpal alignment on lateral radiographs.

An alternate method of diagnosing carpal instability has been presented. The apparatus is easy to construct and is inexpensive. If the apparatus is used properly, it will enable the technician to obtain consistent and comparable radiograph projections.

Confirmation of differential loading of lateral and central fibers of the extensor tendon.

A measurement technique was developed that enabled us to separate (and exclude) the effects of all viscoelastic moments from that produced by the extensor tendon itself. Knowing this moment at various joint positions allowed us to calculate the effective extensor moment arm at the proximal interphalangeal joint. Measurements made on lateral films enabled us to show which fibers of the extensor complex were tensed at various positions of the joint.