The effects of Cx extension on deformation of intervertebral Disc (IVD) and migration of NucleusPulposus (NP)!! This research paper has changed my thoughts on the theory of Mckenzie approach. Cx pain is the second most prevalent pain, reported among musculoskeletal problems in modern society after low back pain. Mainly!, degenerative changes and the resultant structural abnomalities in the spinal column, mostly at the facet joints and IVD. Facetogenic pain: 39% to 55% Discogenic pain: 16% to 20% Cx extension shifts the NP anteriroly within the IVD, decreased pressure on the painful structures in the posterior region. Cx discs are distinctly different from the Lx discs in terms of their chemical composition, morphology, strucrure, and biomechanics, mainly because of the different functional requirements of teh Cx and Lx spines. For this reason, it would be unwise to postulate Lx extension induce the same impact as Cx extension. Posterior annular bulge decreased in flexion while increased in Cx extension. +++The annular bulge increased in Lx extension.+++ Posterior anular fibrosus (AF) expanded horizontally (horizontal thickness of posterior AF increased) as it was compressed vertically by the angulation of vertebral bodies, which caused the posterior disc margin to bulge further backwards.++++ It is thought that the increased annular bulge in Cx extension may contribute to the decreased of neuroforaminal size and increase of intraforaminal pressure due to the narrowing of bony spance within the foramen. In Cx extension, the NP moved forward relative to the disc margin and the posterior AF bulged further backwards with increased horizontal thickness. Cx extension may clinically effect on Cx discogenic pain resulting from internal disc disruption. --------------------------------------------------- When I was a new graduate physio, I utilised Mckenzie approach that involves Lx extension exercise in prone to my patients with radicular pain. Some patients responded well to it but others got worse symptoms. This may be due to the annular fibrosus bulge during spinal extension that decreases space in the neuroforamen. I am not saying that Mckenzie approach is wrong. BUT its theory still needs further research! There are people who respond well to either Spinal extension or spinal flexion. For example, in carpal tunnel syndrome, median nerve sliding can reduce swelling of the median nerve in the carpal tunnel. Interestingly, splinting the affected wrist can also reduce the swelling in the carpal tunnel. So, assess and treat your patients individually.