: three connective tissue membranes that lie external to the brain and spinal cord; function to cover and protect the CNS, enclose and protect blood vessels supplying the CNS, and contain the cerebral spinal fluid (CSF)
: outermost layer, strongest of the meninges; composed of dense fibrous connective tissue. epidural space
: lies just external to dura mater; filled with fat and blood veins that cushion the spinal cord; site of epidural injections
: separated from dura mater by the subdural (potential) space
that contains only a thin film of fluid
lies just deep to the arachnoid mater; spanned by weblike threads that attach the arachnoid mater to the pia mater; filled with CSF and contains large blood vessels that supply neural tissue.
- Pia mater: innermost later of delicate connective tissue richly vascularized by fine blood vessels; clings tightly to spinal cord surface; extends to the coccyx, covering filum terminale; lateral extensions are called denticulate ligaments
- Cerebral Spinal Fluid: fills hollow cavities of CNS; provides liquid cushion and bouyancy (reducing weight of CNS by 97%). Also helps nourish the brain and spinal cord, remove waste produced by neurons, carry hormones through the CNS
- *composition is similar to blood plasma, but contains more sodium and chloride ions and less protein.
- **100-160mls present in body
= inflammation of meninges; can lead to encephalitis; diagnosed through spinal tap (lumbar puncture)