Straightened lumbar spine with preserved alignment. Well corticated, unfused bony fragment seen involving the anterior margin of superior end plate of L4 and L5 vertebral bodies. Degenerative L4-5 and L5-S1 end plate margins.
Anterior herniation of intervertebral disc resulting in fragmentation of the anterior corner. The mechanism postulated is the difference in sizes of adjacent lumbar vertebral bodies. The superior vertebra being smaller, during a flexion injury squeezes the nucleus pulposus anteriorly into the vertebral end plate resulting in a herniation. It is a type of marginal herniation described by Schmorl.
Classical Schmorl’s herniation is a central herniation involving the mid portion of an end plate due to stress induced changes and trabecular weaknening.