A gross anatomic and histologic study of the innervation of the proximal interphalangeal joint.

The innervation of the proximal interphalangeal joint was studied by gross dissection with magnification and histologic analysis. The joint is innervated by a constant articular branch arising from the palmar proper digital nerve at the level of the midproximal phalanx. This articular nerve bifurcates adjacent to the joint, and its terminal branches enter the joint in the midlateral plane at the junction of the palmar plate and lateral capsule. No contribution to the articular innervation was found to arise from the sensory radial, dorsoulnar cutaneous, and collateral branches of the proper digital nerve that cross the joint. The innervation of the proximal interphalangeal joint is congruent with the palmar sensory innervation and has no relation to the dorsal sensory innervation.