Head: Meninges Flashcards
Cranial meninges
- Membranous coverings of the brain
- Protect brain
- Framework for vessels, venous sinuses, subarachnoid space
3 connective tissue layers of cranial meninges
- Dura mater
- Arachnoid mater
- Pia mater
Epidural Space
- Potential space between dura and skull
Subarachnoid Space
- Between arachnoid and pia
Subdural Space
- Potential space between arachnoid and dura
2 layers of cranial Dura Mater
- Periosteal
- Meningeal
Periosteal layer of cranial Dura Mater
- Strongly adheres to internal cranium
- Continuous with periosteum through foramina
Meningeal layer of cranial Dura Mater
- Fused with periosteal layer except at dural reflections (infoldings)
Dural reflections (infoldings)
- Meningeal layer “reflects” away from periosteal layer
- Forms partitions (dural septa) between parts of the brain
- Divides into compartments
Cranial Dura Mater divisions
- Falx cerebri
- Tentorium cerebelli
- Falx cerebelli
- Diaphragma sella
Falx Cerebri
- Separates cerebral hemispheres, located in brain longitudinal fissure
Tentorium Cerebelli
- Divides cranium into supr- and infra-tentorial compartments
- Creates tentorial notch, where the brainstem extends inferiorly
Falx Cerebri attaches to
- Crista galli
- Frontal crest
- IOP
- Tentorium cerebelli
Tentorium Cerebelli attaches to
- Petrous ridge
- Clinoid processes
Falx Cerebelli
- Separates cerebellar hemispheres
Falx Cerebelli attaches to
- Internal occipital crest
Diaphragma Sellae
- Dural roof over hypophyseal fossa
- Covers pituitary gland
Diaphragma Sellae attaches to
- Clinoid processes
Innervation of the Dura
- Primarily by meningeal branches of trigeminal nerve
- Cervical nerves also innervate dura in posterior cranial fossa
Dural venous sinuses
- Endothelial lined spaces between dural layers
- Receive venous drainage from cerebral veins (from brain) and via emissary veins
Superior Sagittal Sinus
- Superior aspect of falx cerebri
Inferior Sagittal Sinus
- Inferior free border of falx cerebri
Transverse Sinus
- Attached portion of tentorium cerebelli
Sigmoid Sinus
- Continuation of transverse sinus
- Continuous with IJV at jugular foramen
Occipital Sinus
- Attached portion of falx cerebelli
- Communicates with internal vertebral venous plexus inferiorly
Straight Sinus
- Line of attachment of falx cerebri to tentorium cerebelli
- Formed by union of inferior sagittal sinus and great cerebral vein
Sinuses that join with the confluence of sinuses
- Superior sagittal
- Straight
- Occipital
- Transverse
Cavernous Sinus
- Located on both sides of sella turcica plexus of veins
- Communicates with the sup/inf ophthalmic veins anteriorly
Superior Petrosal Sinus
- Connects cavernous sinus to transverse sinus
- Runs along petrous ridge along the petrous ridge
Inferior Petrosal Sinus
- Connects cavernous sinus to the sigmoid sinus/IJV junction
Basilar Plexus
- Runs along the clivus
- Communicates with internal venous plexus
Structures found within the Cavernous Sinus
- ICA and surrounding sympathetics
- Abducens nerve
- Oculomotor, trochlear, maxillary, and ophthalmic nerve are in the lateral wall
Nerves found in the lateral wall of the Cavernous Sinus
- Oculomotor
- Trochlear
- Maxillary
- Ophthalmic
Danger Triangle of the face
- Venous communication between facial vein and superior ophthalmic vein
- Spread of infection from facial area to cavernous sinus
Arterial Dural blood supply
- Middle meningeal artery
- Frontal, and parietal branches
Meningeal branches of Dural blood supply
- Vertebral
- Ascending pharyngeal
- Ethmoidal arteries
Pterion fracture
- Damages middle meningeal artery (or vein) causing a epidural hematoma
