Facet tropism is best described as what?

• A. Symmetry in facet orientation with equal loading.
• B. A disease of facet joints causing widespread systemic pain.
• C. Asymmetry in facet joint orientation between left and right sides; it can lead to asymmetric loading, unilateral facet degeneration, and localized pain.
• D. Radiographic sign of disc herniation at L4-L5.

Answer: (C)

Facet tropism is the uneven orientation of the facet joints on opposite sides at a given spinal level. When the left and right facets aren’t aligned the same way, loading during movement becomes uneven, concentrating stress on one side. This can drive asymmetric wear of that facet joint (unilateral degeneration) and produce localized, sometimes sharp or aching, pain in the involved area. It’s an anatomical variation rather than a systemic joint disease, and it isn’t a radiographic sign of disc herniation. So the description that matches this phenomenon is the asymmetry of facet joint orientation between left and right sides with the potential for asymmetric loading, unilateral facet degeneration, and localized pain.