Schmorl Nodes¶
Definition¶
Schmorl nodes are herniations of disc material (nucleus pulposus) through the cartilaginous endplate into the adjacent vertebral body. They represent vertical (axial) disc herniations, in contrast to disc bulge/herniation, which are horizontal (posterior or lateral) herniations.
Pathophysiology¶
- Weakened endplates allow nuclear material to herniate vertically into the vertebral body
- Associated with axial loading, endplate defects, and disc degeneration
- More common in the thoracic and thoracolumbar spine (T7–L1), where axial loads are greatest
- Also associated with Scheuermann disease in adolescents (multiple Schmorl nodes with wedge vertebrae and kyphosis)
Imaging Findings¶
Radiography¶
- Well-defined lucency or irregularity of the vertebral endplate with surrounding sclerosis
- May have a sclerotic ring (reactive bone)
CT¶
- Focal endplate defect with disc-density material herniated into the vertebral body
- Surrounding sclerotic margin
MRI¶
| Phase | T1 Signal | T2/STIR Signal | Interpretation |
|---|---|---|---|
| Acute | Low (edema) | High (edema) | Active; may be symptomatic; can also demonstrate peripheral enhancement, may mimic metastasis |
| Chronic | Iso to low (sclerosis) | Low (sclerosis) with central disc signal | Stable; typically asymptomatic |
Clinical Pearl
An acute Schmorl node with surrounding marrow edema on STIR can mimic a vertebral body metastasis or fracture. The key distinguishing features are: (1) the defect is centered at the endplate, (2) the central content has disc signal, and (3) the edema pattern parallels the endplate rather than involving the entire vertebral body. Correlation with CT (showing the endplate defect) can confirm the diagnosis and avoid unnecessary biopsy.
Key Points¶
- Schmorl nodes are vertical herniations of disc material through the endplate into the vertebral body
- Most common in the thoracic and thoracolumbar spine
- Acute nodes show marrow edema and may mimic metastasis — endplate-centered location is the clue
- Chronic nodes have a sclerotic rim and are typically incidental
- Multiple Schmorl nodes in an adolescent suggest Scheuermann disease
References¶
- Resnick D, Niwayama G. Intravertebral disk herniations: cartilaginous (Schmorl's) nodes. Radiology. 1978;126(1):57-65. https://pubmed.ncbi.nlm.nih.gov/339268/
- Grivé E, Rovira A, Capellades J, Rivas A, Pedraza S. Radiologic findings in two cases of acute Schmörl's nodes. AJNR Am J Neuroradiol. 1999;20(9):1717-1721. https://pmc.ncbi.nlm.nih.gov/articles/PMC7056208/
- Walters G, Coumas JM, Akins CM, Ragland RL. Magnetic resonance imaging of acute symptomatic Schmorl's node formation. Pediatr Emerg Care. 1991;7(5):294-296. https://pubmed.ncbi.nlm.nih.gov/1754491/
- Hershkovich O, Koch JEJ, Grevitt MP. Schmorl node — a cause of acute thoracic pain: a case report and pathophysiological mechanism. Int J Spine Surg. 2020;14(3):441-444. https://pmc.ncbi.nlm.nih.gov/articles/PMC7343260/
- Nogueira-Barbosa MH, Crema MD, Herrero CFPS, Pasqualini W, Defino HLA. The several faces of Schmorl's node: pictorial essay. Coluna/Columna. 2015;14(4):320-323. https://www.scielo.br/j/coluna/a/X44kCXQ6PXrQQmVkS7r7pLD/?lang=en
- Gaillard F, et al. Schmorl nodes. Radiopaedia.org. https://radiopaedia.org/articles/schmorl-nodes-3