Mechanism
No mechanism has been established whereby traction might relieve pain. Nevertheless, proponents of traction believe that it works, and have speculated on its mechanism of effect (Krause et al. 2000).
There is clear evidence that spinal traction does separate vertebral bodies. However, in the lumbar spine much of the separation observed arises from flattening of the lumbar lordosis (Twomey 1985). In the cervical spine, 30 pounds of...