Library · Anatomy
Meninges
Make it clearer
The brain and spinal cord are not sitting loose inside the bone. They are wrapped in three layers of membrane known collectively as the meninges, and their main job is to protect them.
Each one has its own name and texture. The dura mater is the outer one, tough as its name suggests, and it is really two sheets pressed together. Beneath it comes the arachnoid, a thin, cobweb-like membrane. And the deepest is the pia mater, extremely thin and transparent, stuck to the very surface of the brain.
Between the inner two there is a space, the subarachnoid space, filled with cerebrospinal fluid. The large arteries that carry blood to the brain also run through it.
Think of three wrappings, with a layer of fluid between the inner two. That fluid cushions impacts, brings in nourishment and carries waste away.
In brief
The brain and spinal cord are wrapped in three membranes, the meninges, whose main job is to protect them.
The dura mater is the outermost and has two layers; the arachnoid lies beneath it; the pia mater, extremely thin, clings to the surface of the brain.
Between the arachnoid and the pia mater sits the subarachnoid space, filled with cerebrospinal fluid and holding the brain's major arteries.
Three wrappings, with a layer of fluid between the inner two.
That fluid cushions impacts, delivers nutrients and removes waste.
Sources (1)
- National Center for Biotechnology Information, StatPearls PublishingNeuroanatomy, Cranial Meninges, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated