Brain/Meninges Flashcards
Major Parts of Brain
Cerebrum
Cerebellum
Brainstem (Midbrain, Pons, Medulla)
Falx Cerebri and Corpus Collosum
Falx=separates hemispheres of cerebrum vertically
Collosum=connects hemispheres horizontally
Sulcus
Groove
Gyri
elevation
Lobes
Frontal Parietal Occipital Temporal Insula
Longitudinal Cerebral Fissure
Separates 2 hemispheres
Lateral Sulcus (of Sylvius)
separates temporal and parietal lobes
Vermis
cerebellum’s corpus collosum equivelant
Two major Arteries Supply Brain
Internal Carotid and Vertebral Artery
Basilar Artery
Where the vertebral arteries unite (lower border of pons)
-lies in medial groove of pons
Anterior Inferior cerebellar arteries
One of the branches of the basilar artery
- spring from lower part of basilar
- run laterally along surface of pons to supply inferior surface of cerebellum
Pontine Arteries
4-5 slender twigs travel laterally from basilar to pons
Superior cerebellar arteries
spring from basilar close to its termination
-ramify on upper surface of cerebellum
Posterior Cerebral Arteries
Terminal branches of basilar
Internal Carotid Artery
enter skull through carotid canal and inside skull give raise to branches
Posterior Communicating
branch of internal carotid
-occasional seen to arise from middle cerebral
Middle cerebral
branch of internal
Anterior cerebral
branch of internal
Anterior Communicating artery
2 anterior cerebral arteries are joined by this artery and then enter the median longitudinal fissure
Circle of Willis
Cerebral Arterial Circle
Three layers of Cranial Meninges
Dura Mater-tough outer layer
Arachnoid Mater- thin transparent, avasular layer between the pia and dur
Pia Mater- attached to outer surface of brain, vascular layer
Dura Mater
External Periosteal Layer= endocranium formed by periosteum
Internal Meningeal Layer=strong layer continuos with foramen magnum of spinal dura
Falx Cerebri
Longitudinal fissure of dura
- extends from crista galli of ethmoid bone to internal occipital protuberance
- posterior end it joins w/ upper part of tentorium cerebelli hold up tentorium like a tent
Tantorium Cerebelli
-Partly separates occipital lobe from cerebellum
Attachments:
-anteriorly: clinoid process of sphenoid bone
-laterally: petrous part of temporal bone
-posteriorly: occipital bone
Anterior border is free and allows spinal cord to pass through
Falx Cerebelli
partly separates cerebellar hemispheres
attached to occipital bone
-small vertical dural fold in posterior part of posterior cranial fossa
Diaphragm Sellae
Circular sheet of dura
- suspended between anterior and posterior clinoid processes of the sphenoid bone
- forms a roof over hypophyseal fossa
- allows hypophyseal stalk to go through
Dural Venous Sinuses
Contain blood
- endothelial lined spaces between the periosteal and meningeal layers of dura
- large veins from around brain empty here
- Venous blood coursing the sinuses leave skull at jugular foramen draining into internal jugular vein at jugular bulb
Superior Sagittal sinus
upper border of falx cerebri
- starts at crista galli
- ends at confluence of sinuses
Confluence of Sinuses
located at internal occipital protuberance
-dilated junction for superior sagital, straight, occipital and transverse sinuses
Inferior sagittal sinus
located in the inferior free edge of falx cerebri
-ends in free part of tentorium cerebelli by emptying into straight sinus
Straight Sinus
located at junction of falx cerebri and tentorium cerebelli
-drains into confluence
Transverse Sinuses
Right ad left are continuation of superior and straight sinuses respectively
-follow grood for transverse sinus and end at the petrous bone to become the sigmoid sinus
Sigmoid SInuses
s-shaped groove in bone and empty at jugular foramen
Occipital Sinus
lies in attached border of falx cerebelli
-empties at confluence
Cavernous Sinuses
bilateral sides of sella turcica (middle part of sphenoid)
-receives blood from superior and inferior opthalmic veins and sphenoparietal sinus
Sphenoparietal Sinuses
small sinuses that course along lesser wing
Superior petrosal sinuses
stretch bewtween cavernous and transverse sinuses
Inferior petrosal sinuses
commence at cavernous sinus and drain into the jugular foramen
Emissary Veins
connect dural venous sinuses with veins of outside skull
Arachnoid Granulations
Place for CSF to escape from subarachnoid space into superior sagittal sinus
-consist of arachnoid villi that have one way valves
Blood Supply to Meninges
Menigeal arteries
-middle menigeal artery enters skull through foramen spinosus to supply dura
Nerve supply
Largely CN V
-some CN X and XII
Dura very sensitive to pain resulting from pressure changes
