To measure the range of motion at a joint, the center of the goniometer is positioned at the axis of rotation of a joint, and the arms of the goniometer are aligned with the long axis of the bones of the adjacent segments or to an external reference.

A goniometer is an instrument which measures an axis and range of motion.
The 360 degree Goniometers are manufactured in a strong, clear plastic.v
Has three scales calibrated with the ISOM – International Standards of Measurement System.
30cm and 12″ Goniometer arm length with scale
Main Material: Plastic, Colour: Clear