Arachnoid Mater

The brain is the most important as well as a delicate organ in our system which needs protection.

the brain is protected by 3 layers of different membrane

1. Boney covering of cranium

2. Meninges

3. Cerebrospinal fluid

Meninges are three membranous covering of the brain that lies below the skull

the first layer is the outer dura mater, also called the pachymenix, followed by the middle arachnoid mater and the inner pia mater.

the pia mater and the arachnoid mater are together known as the leptomeninges

Arachnoid mater

arachnoid mater is a thin transparent membrane that surrounds the brain without dipping into its sulci and descends through the spinal cord till the s2 level

Prolongations

• it provides sheaths for cranial nerves as it exits from the skull

• arachnoid vill are small fine like projections that project into the cranial venous sinus and absorb CSF