Conus medullaris
| 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. | |
| Gray's | subject #185 749 |
The conus medullaris (Latin for "medullary cone") is the tapered, lower end of the spinal cord. It occurs near lumbar vertebral levels 1 (L1) and 2 (L2). The upper end of the conus medullaris is usually not well defined.
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 tension that the filum terminale provides between the conus medullaris and the coccyx stabilizes the entire spinal cord.[1]
Blood supply
The blood supply consists of three spinal arterial vessels—the anterior median longitudinal arterial trunk and two posterolateral trunks. Other less prominent sources of blood supply include radicular arterial branches from the aorta, lateral sacral arteries, and the fifth lumbar, iliolumbar, and middle sacral arteries. The latter contribute more to the vascular supply of the cauda equina.
Pathology
Conus medullaris syndrome is a collection of signs and symptoms associated with injury to the conus medullaris.[2]
References
External links
- n3a2p5 at the University of Arkansas for Medical Sciences - "Lower Third of Spinal Cord, MRI"
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