ROM is defined as the full motion possible between two bones. Which option best expresses that definition?

• A. The full movement possible between two bones
• B. The maximum strength of a joint
• C. The speed of joint motion
• D. The angle of a joint in a static posture

Answer: (A)

Range of motion describes how far a joint can move, the full arc available between two bones. It is about movement capacity, not how strong the joint is, how fast it moves, or a position held statically. The best expression captures that idea: the full movement possible between two bones. In practice, clinicians assess active and passive ROM to identify any restrictions in flexion, extension, or other planes, which helps reveal whether tight muscles, ligaments, or joint structures are limiting movement.