A goniometer is an instrument that either measures an angle or allows an object to be rotated to a precise angular position. The term goniometry is derived from two Greek words, gōnia, meaning angle, and metron, meaning measure.
How does your physical therapist get an accurate measurement of how your body is moving?
How does he or she know how much a joint moves? Easy: your PT uses a device called a Goniometer.
Goniometer is a device used in physical therapy to measure the range of motion around a joint in the body.
Goniometer is usually made of plastic and is often transparent. Occasionally Goniometer is made of metal. There are two "arms" of the goniometer: the stationary arm and the movable arm. Each arm is positioned at specific points on the body and the center of the goniometer is aligned at the joint to be measured. There are hash marks on the center of the Goniometer that your physical therapist uses to precisely measure joint range of motion.
When first starting physical therapy sessions, your physical therapist may use a goniometer to obtain a baseline range of motion measurement around a specific joint. After a specific intervention or treatment, he or she may measure again to ensure that the treatment is effective.
Goniometers come in different sizes. Small goniometers are available to measure a range of motion around the joints of your fingers, thumbs, and hands. Large goniometers are used to measure the range of motion around your hips or knees.
Technology and Goniometers
There are also goniometers that strap to your body part that can measure the range of motion while you move. Digital goniometers are also available, but these are rarely seen in a typical physical therapy clinic as they are quite expensive.
Recently, a number of goniometer apps on portable devices like smartphones have become available. These use your device's accelerometer and gyroscopic technology to measure changes in the position of the phone. You simply open the app, place your phone in the correct position on your body part, and move your body through its available range of motion. The app will then measure the amount of motion that occurred around the specific joint. Remember, only a trained professional should be using information about goniometric measurements to make medical decisions.
