The effect of digital nerve block on position sense at the proximal interphalangeal joint of the human index finger.

Position matching at the proximal interphalangeal joint of the index finger in human subjects was tested by passive displacement of the right (target) finger and active matching of the left index finger. In 5 subjects it was found that position matching was grossly impaired after digital nerve block of the matching finger. Typically, subjects hyperextended the matching finger when the target finger was held in extension and hyperflexed the matching finger when the target finger was held in flexion. These results suggest that even with active positioning, joint and cutaneous receptors importantly contribute to the awareness of position at this joint.