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Meninges - Anatomy & Physiology (view source)
Revision as of 15:35, 12 January 2011
, 15:35, 12 January 2011no edit summary
[[Image:meninges.jpg|thumb|right|150px|Diagram of the meninges. Sourced from WikiMedia Commons, attributed to [http://training.seer.cancer.gov/module_anatomy/unit5_3_nerve_org1_cns.html http://training.seer.cancer.gov/module_anatomy/unit5_3_nerve_org1_cns.html]]]
[[Image:meninges.jpg|thumb|right|150px|Diagram of the meninges. Sourced from WikiMedia Commons, attributed to [http://training.seer.cancer.gov/module_anatomy/unit5_3_nerve_org1_cns.html http://training.seer.cancer.gov/module_anatomy/unit5_3_nerve_org1_cns.html]]]
* The CNS is surrounded by several layers of tissue.
* The CNS is surrounded by several layers of tissue.
*# Bone layer
*# Bone layer with periosteum
*#* E.g. the skull and the vertebrae.
*#* E.g. the skull and the vertebrae.
*# Dura-arachnoid layer.
*# Epidural Space
*#* Composed of the dura mater and arachnoid layer in close opposition.
*#* Lies between periosteum and dura in vertebral canal. Contains loose connective tissue, veins and lymphatics. Cushions the cord as it flexes. Can be used for nerve blocks (epidural). In cranium, dura fused with periosteum, one single layer in effect.
*# Dura mater
*#* dense connective tissue
*#* fused with the periosteum of cranium
*#* contains the venous sinuses.
*#* Folds of dura mater
*#*# Falx cerebri- midline fold between cerebral hemispheres
*#*# Tentorium cerebelli- oblique fold between the cerebrum and cerebellum
*#*# Diaphragma sellae- forms a collar around the neck of the pituitary, forms the roof of the hypophyseal fossa
*# Subdural space
*#* Lies between dura and arachnoid (not fused). Potential space containing only lymph-like fluid. Site of subdural hematoma.
*# Arachnoid mater
*#* Delicate, non-vascular connective tissue
*#* Adhered to the skull in the calvaria.
*#* Adhered to the skull in the calvaria.
*# Pia mater.
*# Subarachnoid space
*#* between arachnoid and pia connected by tiny filaments (spider-like)
*#* contains CSF from ventricular system
*#* largest parts are the cisterns
*#*# Cerebellomedullary cistern around the foramen magnum. Used for the collection of CSF
*#*# Lumbar cistern used for lumbar puncture in man
*# Pia mater
*#* highly vascular connective tissue, very closely applied to brain tissue
* The '''epidural space''' lies between the bone layer (skull or vertebrae) and the dura-arachnoid layer.
* The '''epidural space''' lies between the bone layer (skull or vertebrae) and the dura-arachnoid layer.
** Local anaesthetic is injected here in epidural anaesthesia.
** Local anaesthetic is injected here in epidural anaesthesia.