Spine Anatomy

Filum Terminale

  • Fibrous tissue that connects the spinal cord to the bottom of the spine

Conus medullaris

  • Tapered ending of the spinal cord

  • Typically seen around L1-L2

Apical ligament

  • Attaches the tip of the dens to the anterior aspect of foramen magnum

  • Weak

  • Fibrous remnant of notochord

Ligaments of C1-C2

Alar ligament

  • Attaches the dens to the lateral margins of the foramen magnum adjacent to the occipital condyles

  • Strong

  • Limit axial rotation and contralateral lateral flexion of the head

Cruciate Ligament

  • 2 parts

    • Longitudinal

      • Body of C2 to clivus & foramen magnum

      • Does not contribute to stability

    • Transverse part (seen on CT below)

      • C1 lateral masses to tectorial membrane and dura

      • Runs posterior to dens

      • Strong and provides stability

References:

  • Case courtesy of Frank Gaillard, Radiopaedia.org, rID: 59206

  • Case courtesy of Craig Hacking, Radiopaedia.org, rID: 53063

  • Case courtesy of Craig Hacking, Radiopaedia.org, rID: 83605

  • Case courtesy of Matt Skalski, Radiopaedia.org, rID: 45136