Arachnoid mater

A) Functional unit of the nervous system
B) Most superficial and thickest meninx
C) The middle meninx
D) The meninx bound tightly to brain and spinal cord
E) Separates dura mater from periosteum

Arachnoid Mater

One of the three meningeal layers, situated between the dura mater and the pia mater, that surrounds and protects the brain and spinal cord.

Meninx

Refers to the membranous covering of the brain and spinal cord, collectively known as meninges.

Periosteum

The dense layer of vascular connective tissue enveloping the bones except at the surfaces of the joints.