filum durae matris spinalis

[durē mātrĭs spī-nālĭs]
n.
  1. The termination of the spinal dura mater, surrounding the terminal filum of the cord and attached to the deep dorsal sacrococcygeal ligament.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.