Spinal dura mater (dural sac)
Dura mater spinalis
NervousOrgansWhole body
- What it is
- The tough tube of dura that continues the cranial dura through the foramen magnum and encloses the spinal cord, CSF and cauda equina, ending as a blind sac at the level of S2; each nerve root takes a sleeve of it into its foramen.
- Function
- Protects the cord and holds the CSF of the spinal subarachnoid space; the fat-filled epidural space outside it cushions it against the bone.
- Size
- About 45-50 cm long; 1.5-2 cm across; ends at S2
- Clinical note
- Epidural anaesthesia is injected outside this sac; a spinal anaesthetic or lumbar puncture pierces it (and the arachnoid) below L2 to reach the CSF.