The position of the round vertebra is lower than the normal half or two vertebral bodies, and the terminal filament is only slightly thickened, and the diameter of the terminal filament is larger than1.5 mm. This slight terminal filament thickening is not easy to determine on MR, so the final terminal filament thickness is1.5 mm.
The terminal filament is a meningeal filament of non-nerve tissue, which is connected with the end of the conus medullaris and the dorsal side of the coccyx.