CT identification of the posterior limbus vertebra

Herniation of the lumbar nucleus pulposus into the posterior apophyseal ring is difficult to recognize on axial computed tomographic (CT) scans and is often misinterpreted as a calcified disk protrusion. Twenty-two patients with posterior limbus vertebra (11 with histories of moderate or minor trauma) were identified with the use of routine sagittal lumbar Ct reformations. The diagnosis of posterior limbus vertebra requires reformations perpendicular to the axial CT scans and because of its frequent traumatic origin has medicolegal implications significantly different from the calcified disk or osteophyte with which it is often confused