Presentation
Low back pain after lifting a heavy object. Referred for a lumbar spine MRI.
Patient Data
A well-corticated triangular bony fragment is seen at the left inferior articular process of L3, in keeping with an Oppenheimer ossicle. It demonstartes a hyperintese signal on T1 and T2, which is suppressed on STIR, reflecting fat metaplasia.
Intervertebral disc disease in the form of a central annular fissure at L4-L5 and a broad-based central protrusion at L5-S1. No canal stenosis or nerve root compromise.
Annotated sagittal and coronal T2 weighted images:
Oppenheimer ossicle (red arrow)
Case Discussion
Usually an incidental finding, an Oppenheimer ossicle is an accessory structure resulting from a horizontal cleft through the inferior or less commonly the superior articular processes in the lumbar spine.
It can be mistaken for a pars interarticularis fracture or, rarely, for a calcified ligamentum flavum in older patients.