Range of motion is the natural distance and direction of movement of a joint.
Limited range of motion is a relative term indicating that a specific joint or body part cannot move through its normal and full range of motion. Motion may be limited by a mechanical problem within the joint that prevents it from moving beyond a certain point, by swelling of tissue around the joint, by spasticity of the muscles, or by pain. Diseases that prevent a joint from fully extending may, over time, produce contracture deformities , causing permanent inability to extend the joint beyond a certain fixed position. There may be other causes of limited range of motion. This list is not all inclusive, and the causes are not presented in order of likelihood.