Structure
The filum terminale internum is the superior portion of the filum terminale that runs from the conus medullaris, inferiorly, to the filum terminale externum. The filum terminale internum forms the majority of the length of the filum terminale and is generally the portion seen in cadaveric specimens. The filum terminale internum is composed of pia mater. In cadaveric specimens, it often is distinguishable from spinal nerve roots due to its silvery to opaque appearance.
Related parts of the anatomy
Key Features/Anatomical Relations
When the spinal cord terminates at roughly the L1-L2 vertebral level in adults, the overlaying pia mater continues down, forming a collapsed tube of pia mater. Together with denticulate ligaments, the filum terminale internum can be seen with the naked eye.
