The dura mater is the outer tough covering of the meninges of the central nervous system. A little bit of knowledge about this structure can provide some therapeutic stories. Some of the information is quite old – after all, dura is not a trendy research topic – most people focus on the gray and white matter that it protects.
Maybe it’s more important that we realise…
Six dural nuggets:
- Spinal dura is continuous with the cranial dura and with the epineurium (the outer sheath of connective tissue) of peripheral nerves.
- Flex your neck and/or pull your head in and the lumbar dura slides and tensions. Passive Neck Flexion (remember that one!) will reproduce back pain in around a quarter of all people with back pain (Troup 1981). Few people know this as few people examine for it. The finding could be threatening without explanation.
- Dura is not an inert tube. It is innervated especially on the side near the disc – the dorsal side is hardly innervated thus lumbar punctures may not cause nociception and hence perhaps no pain.
- Afferent meningeal nerve endings (sinuvertebral nerve) are highly responsive to mechanical stimuli but as they contain mast cells, macrophages and dendritic cells they are influential sites of immune regulation and potential major sites of inflammatory events in states such as multiple sclerosis, stroke and trauma (Christy et al 2013).
- Dura is really strong, especially in the longitudinal orientation, but not so much laterally (Zarzur 1996) – forces that shift the dura laterally, perhaps forced limb movement from a motor bike accident or surgical nicks may split the dura and lead to a CSF leak that can “deflate” the meninges leading to symptoms such as headache.
- Your spinal canal is 7-9 centimetres longer in flexion than extension however dura, dural attachments and other meningeal layers somehow allow the central nervous system to adapt mechanically while we move and yet still allow conduction, learning and plastic changes – so perhaps it could be worthwhile taking a little more notice of this remarkable structure.
Christy AL et al 2013 Journal of Autoimmunity 42:50
Troup JDG 1981 Spine 6:526
Zarzur E 1996 Arquivos de Neuropsiquiatrica 54:455
Neuroscience nuggets are information nuggets – pieces of biological information based on statement or metaphor that can be used as educational analgesia, explicit education or part of overall story telling. We have collected over 100 of these for a book and will release one or two a week with a short description and references if appropriate.
Learn about dozens of other neuroscience nuggets as you get your think on and get up to date at a noigroup course. You can also immerse yourself in some brainy books with Explain Pain 2nd Ed and The Graded Motor Imagery Handbook
Interesting I patient I had with sudden muscle spasms and small involuntary movement, specially in the lower limbs at passive and active neck movement (not always but several times a day) and cephalalgia, first thought to be an upper motor neuron lesion at the cervical medulla/ spinal cord. Nothing showed in complementary exams. She had fallen months earlier on her ‘bottom’. Treatment was cranial/sacrum and neural mobilisation. Symptoms abolished for a period of months after 2 tt.
Thank you sweetheart, you’re reminders of the structure-our body- which enables us to act out our thoughts, feelings and emotions are vitally important. One way or another, the unique conclusions that each and everyone of us arrives at with our clinical reasoning have to be fed back into the being to bring about change …………
Thanks Bruno and David,
I think it is still forgotten that all the remarkable plasticity, communication, networking and learning that occurs in the trillion or more cells in the central nervous system is all for nothing if the meninges cannot provide an effective system of mechanical /inflammatory defence.