Sacrococcygeal pain syndromes: diagnosis and treatment.

Sacrococcygeal pain can arise from the sacrococcygeal joint, from contiguous structures sharing the same innervation, or from distant sites. True coccygodynia consists of pain arising from the sacrococcygeal joint, whereas pseudococcygodynia consists of pain referred to but not arising from the coccyx. Coccygodnia can usually be distinguished from pseudococcygodynia by physical examination with the diagnosis being confirmed by injection of local anesthetic into the sacrococcygeal joint. The etiology of pain not relieved by intraarticular injection can be further defined by selective neuroblockade. A method for defining the anatomic basis for sacrococcygeal pain is presented as well as a discussion of the relevant anatomy and differential diagnosis of sacrococcygeal pain.