Conus medullaris
The conus medullaris (Latin for "medullary cone") or conus terminalis is the tapered, lower end of the spinal cord. It occurs near lumbar vertebral levels 1 (L1) and 2 (L2), occasionally lower. The upper end of the conus medullaris is usually not well defined, however, its corresponding spinal cord segments are usually S1–S5.
| Conus medullaris | |
|---|---|
Cauda equina and filum terminale seen from behind. The dura mater has been opened and spread out, and the arachnoid mater has been removed. | |
| Identifiers | |
| TA98 | A14.1.02.004 |
| TA2 | 6052 |
| FMA | 74897 |
| Anatomical terminology | |
After the spinal cord tapers out, the spinal nerves continue to branch out diagonally, forming the cauda equina.
The pia mater that surrounds the spinal cord, however, projects directly downward, forming a slender filament called the filum terminale, which connects the conus medullaris to the back of the coccyx. The filum terminale provides a connection between the conus medullaris and the coccyx which stabilizes the entire spinal cord.