A review of biomechanics of the central nervous system. Part I: Spinal canal deformations caused by changes in posture

Abstract

Finally, extension is questioned in treating low back pain. A study showed that spinal manipulation and an ongoing flexion and extension exercise program resulted in more rapid resolution of symptoms and improvement in functional limitations than an established extension program alone.62 Other well-done articles63–66 question the extension principles cited by Harrison et al.1 This does not mean extension posturing is not helpful but rather that it is part of therapy. The same is true of flexion posturing—it is not the total answer for back pain but offers a significant benefit to be used by the practicing chiropractor in the daily care of patients.Rather than only being a 1- to 1.5-mm change in the sagittal diameter of the spinal canal and intervertebral foramen in extension motion, as stated by Harrison et al,1 the articles cited in this reply show that the combined narrowing in extension by the disk herniation, ligamentum flaval hypertrophy, and buckling can approach 10 mm. These true changes in canal diameter on motion demand therapeutic consideration and demand patient tolerance testing before flexion or extension adjusting is undertaken.