Trunk nerves (intercostal, sympathetic, vagus nerve)
Spinal dura mater (Dura mater spinalis)
Dura mater spinalis
- Origin
- Begins at the foramen magnum as the continuation of the inner layer of the cranial dura mater
- Insertion
- Ends as the dural sac at S2 and continues as the external filum terminale, which attaches to the coccyx
- Function
- Tough outer membrane around cord, roots and cauda equina; together with the arachnoid it encloses the subarachnoid space with its cerebrospinal fluid and protects the cord mechanically
- Innervation
- Sensory through the meningeal branches (sinuvertebral nerves) of every spinal nerve
- Movement & chain
- Glides within the vertebral canal during flexion and extension of the spine
- Palpation
- Not palpable; the space outside it is reached with an epidural catheter, the space inside it with a lumbar puncture
- Clinical
- A lumbar puncture and spinal anaesthesia pass through the dura below L2, epidural anaesthesia stops just in front of it; post dural puncture headache comes from cerebrospinal fluid leaking through the hole. Also accidental dural puncture during an epidural, epidural haematoma and spinal epidural abscess. The dural sac continuing to S2 while the cord already ends at L1-L2 is exactly what makes a puncture at L3-L4 safe.
- Segmental innervation
- From the foramen magnum to S2
- In clinical practice
- Assisting with lumbar puncture and epidural insertion, guarding positioning and sterility, and observing afterwards for post dural puncture headache and neurological deficit
- Region in the model
- Trunk nerves (intercostal, sympathetic, vagus nerve)