• The meningeal layer folds up to form dural infoldings that divide the cranial cavity into different compartments:
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  • Meninges
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  • The brain and spinal cord are enclosed in three protective membranes called meninges.
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  • From without inwards these are:
  • (a) dura mater, (b) arachnoid mater, and (c) pia mater.
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  • The dura mater is mesodermal in origin while arachnoid and pia mater are ectodermal in origin (derived from neural crests).
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