Spinal Cord Structure
The spinal cord is located within the spinal canal, which is created by bony vertebral structures and a ligamentous network. This canal provides stability and protection for the spinal cord, which extends from the foramen magnum to approximately the 1st or 2nd lumbar (L1-L2) vertebral interspace in adults. It ends at the conus medullaris.
Fibrous bands extend from the conus medullaris to fix the spinal cord to the coccyx. The tissues surrounding the spinal cord are called meninges. The outermost area is called the epidural space, followed by the dura mater, which is a tube that contains cerebrospinal fluid (CSF) and may extend up to the S1 level in adults and S3 in infants.
Termination of Spinal Cord
- Adults: usually ends at L1
- Infants: ends at L3
There are anatomical variations. For most adults, it is generally safe to place a spinal needle below L2.
