ABSTRACT
Facet tropism is defined as asymmetry in the facet joint angles of lumbar vertebreas. in the text books there is no subject about it but there are many title and article about this anomaly and the effect of it on lumbar pain. This study tries to evaluate prevalence of facet joint tropism in the patient with low back pain. During one year, 350 patients were referred to Emam Reza Hospital due to low back pain without any ethiologic factors like acute trauma, infection, tumor or Spinal deformity. The patients were evaluated with lumbosacral radiography and for patients with asymmetry of facet joint, CT Scan was performed. Then the angle of facet joint in both sides of vertebrae was measured. Altogether the Facet tropism were seen in 68 patient [19%] and 43 cases [63%] in L5-S 1 were the most common location among these vertebreas. this study shows that facet tropism can be considered as a predisposing factor for low back pain