Chronic low back pain is a common problem. Lifetime adult prevalence rates vary from 50 to 80%, and around a quarter of adults say they have experienced back pain during the past month. One in 40 report disabling back or neck pain. Each year around 7% of patients consult their GP with back pain. In 65-70% of primary care patients with low back pain there is no known pathoanatomical cause. Their pain is described as nonspecific and is postulated to arise from muscle strain or ligamentous injury. A further 15-20% of patients have mechanical low back pain with an identifiable cause such as degenerative disc or joint disease.