The term goniometry is derived from two Greek words, gonia, meaning angle and metron, meaning measure. Therefore, goniometry refers to the measurements of angles created at human joints by the bones of the body. When using a universal goniometer, the examiner obtains these measurements by placing the parts of the measuring instrument along the bones immediately proximal and distal to the joint being evaluated. For example, let’s say we want to test how far a patient can bend his elbow. We put the arms of the goniometer along the arm bones and measure the elbow when it’s straight and then fully bent. Normally, this range is 180 degrees. Source: Norkin, Cynthia and White, D. Joyce. 'Measurement of Joint Motion, 2nd Edition'1985