A commentary from the pioneers on the innovation of the relative motion concept: History, biologic considerations, and anatomic rationale

Relative motion is not an orthosis. It is a concept about the normal functional anatomy that may be harnessed and controlled to a beneficial degree by orthoses. Simply stated, the relative motion (RM) concept is recognition that the normal powerful extensor digitorum communis (EDC) and flexor digitorum profundus (FDP) extrinsic muscle forces on the metacarpophalangeal joints (MCPJs), proximal interphalangeal joints (PIPJs) and distal interphalangeal joints (DIPJs) in finger digits significantly vary between digits when there are relative differences in position between their adjacent MCPJs, whether held by an orthosis or not.

Source: Journal of Hand Therapy - April 7, 2023 Category: Rehabilitation Authors: Wyndell Merritt, Sandra Robinson, Maureen Hardy Source Type: research