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Limbus vertebra is a benign, developmental anomaly resulting from the herniation of the nucleus pulposus through the cartilaginous vertebral endplate beneath the ring apophysis before fusion.
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It is not a fracture, though it may mimic one in trauma settings
Epidemiology:
Location
| Location | Frequency |
|---|---|
| Anterior-superior vertebral margin (most common) | >90% |
| Posterior margin (rare) | Potentially symptomatic due to cord or nerve root compression |
| Modality | Imaging features |
|---|---|
| XR | • Triangular or rectangular bony fragment at the anterosuperior corner of the vertebral body |
| • Well-corticated margins, separate from the main vertebral body | |
| • Commonly mistaken for a healed compression fracture fragment or avulsion | |
| CT | • Best modality for bony detail |
| • Clearly shows corticated fragment with no signs of acute fracture | |
| • No edema or soft tissue swelling | |
| MR | • Shows adjacent disc degeneration (if present) |
| • Posterior limbus vertebra may compress the thecal sac or nerve roots | |
| • No marrow edema in chronic lesions |
https://www.youtube.com/watch?v=gdxLJ1B-e5Y
CT imaging:
The radiography of the lumbar spine (1a) revealed a large bony fragment over the anterosuperior portion of the third lumbar vertebral body (arrow). 3D volume rendering imaging of sagittal computed tomography (1b) showed one large well-corticate with sclerotic margin, triangular bone fragment on anterior and superior endplate of L3 vertebrae (arrowhead), a finding that is compatible with limbus vertebra.
Y. Yen, F.-Z. Wu, Giant limbus vertebra mimicking a vertebral fracture, QJM: An International Journal of Medicine, Volume 107, Issue 11, November 2014, Pages 937–938, https://doi.org/10.1093/qjmed/hcu074
MR imaging:
Limbus vertebra: (A) lateral radiograph of lumbar spine. The image shows the irregularity of the superior and anterior corners of the vertebral body at lumbar 3 (L3). The L2–L3 intervertebral space is narrowed. There are small anterior osteophytic formations at L2 and L4. The density of the vertebral bodies is conserved; (B) computed tomography with sagittal multiplanar reconstruction, in which the irregularity of the anterosuperior margin of L3 vertebral body can be seen in greater detail. Sclerosis can be observed both in the recessed vertebral endplates and around the osseous fragments separated from the rest of the bone. Listhesis can also be detected at L3–sacral 1 (S1) and Schmorl's node in the superior endplate at L1; (C) magnetic resonance imaging (MRI) of sagittal spin-echo T1-weighted (SET1) sequences. The intensity of the vertebral bodies is conserved and the osseous fragment separated from the L3 body has the same signal intensity has the rest of the bone; (D) MRI of sagittal spin-echo T2-weighted sequences. The findings complement what can be observed in the SET1 sequence. There is a decrease in height and signal of intervertebral discs at L2–L3, L3–L4 and L5–S1 in relation to dehydration in the setting of a degenerative disc disease. There is also a posterior central disc herniation at L5–S1, that migrated cranially, accompanied by listhesis; (E) MRI sagittal SET1 sequences in-phase and out-of-phase. In these sequences, the signal of the disc cartilage is high and bright. It can be seen how it is introduced between the osseous fragment and the foremost region of the superior L3 endplate; (F) drawing representing the changes observed in the images to the left. It can be seen that the L2–L3 intervertebral disc is introduced through the anterior surface of the L3 vertebral body. A Schmorl node can also be seen in the superior endplate of L1 and a protrusion of the L5–S1 disc, with a posterior central disc herniation, accompanied by listhesis at L5–S1.
Cubero CC, Duarte, Gil, Luis J. Mechanical Low Back Pain as a Presentation of Anterior Limbus Vertebra. Reumatología Clínica (English Edition). 2017;13(3):176-177. doi:https://doi.org/10.1016/j.reumae.2016.02.011