Meninges

Meninges
1. Membranous lining (3 layers, dura, arachnoid, pia) of the brain and spinal cord

General
1. Mnemonic: PAD
Pia Mater (inner layer, adjacent to brain)
1. Inner layer of the Meninges (adjacent to the brain)
2. Vascular layer (contains the major intracranial arteries including the Circle of Willis)
Arachnoid Mater
1. Connective tissue space between the dura and the pia
2. Subarachnoid space separates the arachnoid from the pia
  1. Contains cerebrospinal fluid
  2. Subarachnoid Hemorrhage occurs in this space
Dura Mater (outer layer, adjacent to skull)
1. Thick, durable, outer layer of the Meninges (adjacent to the skull)
2. Composed of two layers of connective tissue between which run cerebral veins known as sinuses
3. Forms two additional barriers between intracranial components
  1. Falx Cerebri (divides the Cerebral Hemispheres)
  2. Tentorium cerebelli (divides the Cerebrum from the Cerebellum)
4. Pathophysiology
  1. Subdural Hemorrhage occurs when veins bridging the brain and dural sinuses rupture
  2. Epidural Hemorrhage occurs when the middle meningeal artery ruptures (between the dura and skull)