4th June 2023

Basic spinal cord anatomy

The spinal cord extends from the medulla oblongata in the brainstem to the conus medullaris at the level of L1-L2 in the lumbar spine. It then forms a fibrous extension called the filium terminale, connecting the conus medullaris to the coccyx, stabilising the spinal cord. The filum terminale is surrounded by a bundle of nerves forming the cauda equina.

The spinal cord and brain are surrounded by three layers of membranes known as the meninges. The pia mater is the innermost layer, tightly adherent to the surface of the brain and spinal cord. The arachnoid mater is the middle layer, and the space between the pia and the arachnoid mater is called the subarachnoid space; this space contains CSF. The outermost layer is the dura mater. The epidural space refers to the area between the dura mater and the surrounding vertebral wall, and contains small blood vessels, lymphatics, and adipose tissue.