Limbus vertebra is a well-corticated osseous density, usually of the anterosuperior vertebral body corner, that occurs secondary to herniation of the nucleus pulposus through the the vertebral body endplate beneath the ring apophysis. These are closely related to Schmörl nodes and should not be confused with limbus fractures or infection. They occur before the age of 18.
Limbus vertebrae should be well corticated (sclerotic margin), triangular in shape and occupy the expected location of a normal vertebral body corner, with a smooth subjacent corticated vertebral margin.
A limbus vertebra of the anterosuperior corner of a single vertebral body in the mid lumbar spine is the most common presentation. The anteroinferior and posterinferior corners are seen far less frequently. Occasionally it may be seen in the thoracic spine.
Usually radiography with or without CT or MRI is sufficient for diagnosis. Initially the etiology was confirmed with discography where contrast extends into the intra-osseous herniation of the nucleus pulposis.