A goniometer is an instrument which measures the available range of motion at a joint. If a patient or client is suffering from decreased range of motion in a particular joint, the therapist can use a goniometer to assess what the range of motion is at the initial assessment, and then make sure the intervention is working by using the goniometer in subsequent sessions.
The term goniometry is derived from two Greek words, Gonia, meaning “angle” and matron, meaning “measurement”.