Although low back pain is typically considered to be multifactorial, it is estimated that facet arthropathy accounts for up to 40% of all cases of low back pain, 15% of work injury-related back pain, and 16% of cases of postlaminectomy syndrome. The zygapophyseal joints are true synovial joints and are located in the posterolateral aspect of the lumbar vertebral column. Risk factors for chronic low back pain include increasing age, weight (body mass index [BMI] >30), female gender, genetic factors, and smoking. Facet joints have a complex and dual innervation. Each joint receives innervation from two adjacent medial branches, one at the same level and one from the level above.