After completing “The Meninges” section, you will be able:
- To explain the purpose of the meninges
- To describe each layer of the meninges
- To demonstrate the order of the maters
- To apply knowledge to evaluate the spaces between the maters
- To validate knowledge by completing the quiz
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What are the meninges?
The meninges consist of three membranous connective tissue that enclose the brain: pia mater, arachnoid mater and dura mater.
Purpose of the meninges
Protect the brain
Form the supporting framework for arteries, veins and venous sinuses
Enclose a fluid-filled (CSF) cavity, the sub-arachnoid space, which is vital to the normal function of the brain.
* Mnemonic Alert: P–A–D (deep to superficial). The meninges form a PAD around the brain *
P – Pia: thin vascular layer containing network of fine blood vessels.
A – Arachnoid: intermediate layer, with the sub-arachnoid space deep to the arachnoid mater.
D – Dura: thick, tough fibrous outer layer.
Spaces between maters
The spaces between the maters are areas where blood collection from trauma can occur:
- Extradural/epidural space = unnatural space developed between the skull/cranium and dura mater. Blood from a torn middle meningeal artery pushes the periosteum away from the cranium.
- Subdural space = unnatural space developed between the dura and arachnoid mater.
- Subarachnoid space = natural space between arachnoid and pia mater containing a web-like framework of cerebrospinal fluid (CSF), trabecular cells, arteries and veins.