How to Measure Range of Motion of Forearm Supination

Young woman laughing with outstretched arms

Forearm supination is the amount of movement involved when the arm rotates into a palm-upward position. Although this measurement varies based on individual bony structure and mobility, as well as soft tissue tension, the average is 80 to 90 degrees. Full range of motion is important to maintain to allow for activities of daily living. Accurate assessment can be difficult to obtain without training and practice, but a measurement for general purposes can be done if proper care is given to each step.

Range of Motion

Bend the elbow to 90 degrees, while holding the flexed elbow at the waist to eliminate shoulder involvement.

Grip a pencil in the hand, with the pencil pointing toward the ceiling.

Rotate the forearm to the outside until the end range is reached. The pencil should now be parallel to the floor for normal range of motion.


Align the two arms of the goniometer with the pencil so that they are pointing at the ceiling.

Stabilize the stationary arm in this position, while moving the second arm directly in line with the pencil during rotation.

Record the final number. This should be in the 80- to 90-degree range.


Bilateral comparison is helpful.


Avoid pushing through pain unless directly supervised and instructed by a medical professional.