From foramen magnum to:

  • Embryonic period - Coccygeal
  • 24 weeks - S2
  • Birth - L3
  • Adult - L1 / L2 junction

Embryonic basis: Faster growth of the vertebral column than the spinal cord.

The conical of the spinal cord is called the conus medullaris. After the termination, the spinal nerves follow the lumbar and sacral curves. These together with filum terminale form cauda equina.



  1. Cervical enlargements (C4-C8) corresponding to origin of the brachial plexus.
  2. Lumbrosacral enlargement (L2-S3) corresponding to origins of the lumbar and lumbrosacral plexi.




•  Vertebral column

•  Spinal meninges

• Cerebrospinal fluid

Support and anchorage

  • Spinal nerves

  • Continuation with brain stem

  • Denticulate ligaments