The arachnoid is one of the three membranes that cover the brain and spinal cord.
Арахноид - это одна из трех оболочек, покрывающих мозг и спинной мозг.
Definitions
A thin, delicate membrane that is part of the three layers of the meninges surrounding the brain and spinal cord, situated between the dura mater and the pia mater.
The surgeon carefully examined the arachnoid to ensure there was no damage during the procedure.