Computerized tomography of the Cupid's bow contour of the lumbar spine.

The inferior endplates of the third, fourth, and fifth lumbar-vertebral bodies frequently have paired parasagittal concavities when viewed in the frontal projection. In the lateral projection, these concavities lie posteriorly and are superimposed. This has been called Cupid's bow contour of the spine. On CT, Cupid's bow is visualized in an axial plane as two rounded relatively well-circumscribed areas of hypodensity rimmed by apparant osteosclerosis in the posterior half of the vertebral bodies. This, on occasion, may resemble metastasis or other pathology of the spine. The CT features, however, once appreciated, are characteristic of this normal variant, helping to distinguish it from other contour deformities of the vertebrae having clinical significance. The CT features are described and the incidence is discussed in 100 patients.