Posterior ring apophysis fractures occur in the immature skeleton, most commonly in the lumbar spine.
Typically, adolescent males practicing sport activities.
- back pain
- muscle weakness related with root innervation
- association with Scheuermann disease
The ring apophysis is the part of the vertebral body connected to intervertebral disc. It is firmly attached to disc fibrous annulus through Sharpey fibers and its ossification occurs at 4-6 years old.
In the first years of life, the junction between ring apophysis and the rest of vertebral body is made through a cartilage layer, that is only completely ossified around 18 years old, and this is a weak point.
Repeated trauma or stress forces can cause disc herniation through this layer causing ring apophysis fractures.
Considered best imaging modality. Findings include:
- osseous fragment displaced posteriorly to endplate with rectangular or arc shaped morphology on axial plane
- posterior endplate defect
- posterior disc herniation
- high T2/STIR signal of acute fracture
- corner defect on posterior endplate margin
- disc degeneration and loss of height
- best method to evaluate nerve root / cauda equina compression
On imaging consider
- Schmorl's node
- disc calcification/ossification
- calcified disc fragment
- posterior osteophyte
- 1. Yen CH, Chan SK, Ho YF, Mak KH. Posterior lumbar apophyseal ring fractures in adolescents: a report of four cases. Journal of Orthopaedic Surgery 2009;17(1):85-9.
- 2. Anthony C Tibbles, Pierre Côté, J David Cassidy, and J Donat. Adolescent apophyseal ring fracture simulating lumbar disc herniation: a case report. J Can Chiropr Assoc. 1992 Mar; 36(1): 11–16.
- 3. Brant-Zawadzki M (2004). Apophyseal Ring Fracture. In Ross JF (ed), Diagnostic Imaging Spine (pp.II-I-94-97). Altona, Manitoba, Canada: Amirsys.