The paper outlines a method of monitoring changes in joint angle for a 2-dimensional movement of the limbs. The transducer described is acceptably linear over a range of 100°. It provides a useful alternative to goniometry in situations where the attachment of a goniometer across the joint would cause undue interference to the movement being studied. The transducer detects spatial movement by measuring the voltage induced in a sensing coil from a 1 MHz magnetic field produced by a small solenoid. 3-dimensional monitoring of body movements is discussed and shown to be feasible using a more complex system.