[Isolated septic arthritis of the articular surface of the lumbar spine--the contribution of MRI].

We describe the case of a 54 year-old-woman which isolated septic arthritis of the lumbar facet joint resulting from staphylococcus aureus. This infection is a rare condition, there are only a few previously reported cases of isolated septic arthritis of the facet joint in the literature. MRI is the preferred imaging method of diagnosis because of the ultiplanar imaging capability and the excellent soft tissue haracterization.