Low back pain is a common condition.Although the evolution of medicine, find new analgesics, new techniques, and new neurosurgical diagnostic procedures, the clinical results are not always satisfactory and there are many patients with partial improvement and chronic pain.We believe that the lumbar spine is a functional unit, that includes not only strictly lumbar region but also the pelvic, sacral, and coccygeal.That lumbosacrococcigea functional unit (UFLSC) is included not only the bony structures (vertebrae) and cartilage (intervertebral discs) but also the muscle and neural structures.In this paper we present a review of the literature, on the theoretical and clinical aspects that support this theory.These concepts serve to establish a prognostic factors for treatment of back pain.