Cranial Contents Flashcards
Cavernous sinuses
On either side of the sella turcica (sphenoid)
Gets blood from ophthalmic veins, superficial middle cerebral vein, sphenopareital sinus
Communicate with eachother via intercavernous sinuses
Drain posteriorly into the superior/inferior petrosal sinuses
Structures that run through sinus: internal carotid artery, oculomotor nerve, trochlear nerve, ophthalmic and maxillary divisions of trigeminal nerve, abducens nerve
How does the middle menangial artery enter the skull?
Foramen spinosum
What is the primary artery of the dura mater?
Middle menangial artery
How does CSF leave the ventricles and enter the blood stream?
Leaves through apertures in the 4th ventricle (near brainstem/cerebellum) into the subarachnoid space
It then enters superior sagittal sinus via arachnoid villi
What structures run through the center of the cavernous sinuses?
Internal carotid artery
Abducens (CN VI)
Emissary veins
Veins connecting diploic veins to the superior sagittal sinus
Epidural hematoma
Aka menangial artery tear
Caused by fracture in skull = tear in menangial artery
Leads to bleeding of arterial blood between dura mater and skull
Falx cerebri
Double layer of meningial dura
In the longitudinal fissure separating the cerebral hemispheres
Extends from crista galli (ethmoid) - internal occipital protuberance (occipital)
Reduces side to side movement of the brain
What are the pathways for venous drainage from the scalp?
Can directly drain into internal/external jugular veins
OR
Drain into diploic veins - emissary veins - superior sagittal sinus
Tentorial notch
Hold in tentorium cerebelli through which the brainstem travels
Subdural hematoma
Aka cerebral vein tear
Venous blood collects between dura and arachnoid mater
Which part of the brain sites in the middle cranial fossa?
Temporal lobes
Superior petrosal sinuses
Drain blood from cavernous sinuses - transverse sinuses (as they become the sigmoid sinuses)
At crest of petrous part of temporal bone
Tentorum cerebelli
Separates occipital lobes of cerebrum from the cerebellum
Attached to pterous portion of temporal bone - anterior clinoid processes (sphenoid)
Tentorial notch: hole through which brainstem travels
Supports posterior cerebrum so it doesn’t compress cerebellum
Which artery can be torn when there is a fracture at the pterion?
Middle menangial artery
Sigmoid sinuses
S shaped
Run in posterior cranial fossae (grooves)
Gets blood from transverse sinuses to jugular foramen - internal jugular vein
Which layer of the dura mater is considered to be the “true dura”?
Meningeal dura mater
Circle of Willis
Circular anastomotic communication of the arteries at the base of the brain Contributing arteries: - Basilar - posterior cerebral - posterior communicating - internal carotid - middle cerebral - anterior cerebral - anterior communicating
What is the significance of blood from the scalp being able to drain into diploic veins?
Infections on the scalp can enter brain through venous drainage pattern
Scalp - diploic veins - emissary veins - superior sagittal sinus
Sphenopareital sinus
In edge of lesser wing of sphenoid
Drains into cavernous sinuses
Straight sinus
Between falx cerebri and tentorium cerebelli
Receives blood from inferior sagittal sinus, great cerebral vein
Drains into confluence of sinuses
Which nerves relay sensory information from the meninges?
All divisions of the trigeminal nerve (CN V)
C2, C3
Meningeal layer that forms septae
Meningeal dura mater
Inferior sagittal sinus
Along inferior edge of falx cerebri
Joins with great cerebral vein (of Galen) to empty into straight sinus
Where is CSF in the brain?
Subarachnoid space
Confluence of sinuses
Receives blood from superior sagittal sinus, straight sinus
Drains into transverse sinuses on either side
Which part of the brain sits in the posterior cranial fossa?
Crerebellum
What structures run through the lateral walls of the cavernous sinuses? (From superior to inferior)
Oculomotor (CN III)
Trochlear (IV)
Opthalmic divison of trigeminal (V1)
Maxillary division of trigeminal (V2)
Meningeal layer attached to internal periosteum (endocranium)
Periosteal dura mater
Which part of the brain sits in the anterior cranial fossa?
Frontal lobes
Great cerebral vein (of Galen)
True vein - drains blood from deep brain - straight sinus
Superior sagittal sinus
Runs longitudinally along midline of skull
Receives blood from cerebral veins
Flows anterior-posterior - confluence of sinuses
Also receives CSF from subarachnoid space via arachnoid villi
Diploic veins
Veins within the flat bones of the skull
Drain into superior sagittal sinus via emissary veins
Symptoms of tumors of the pituitary gland
Can cause diaphragma sellae to bulge superiorly and press on optic chiasma, causing visual symptoms as well as endocrine symptoms
What forms the blood-brain barrier
Brain capillaries - continuous basement membrane, tight junctions
Astrocytes - perivascular feet
Subarachnoid hemorrhage
Aka cerebral artery rupture
Arterial blood collects in subarachnoid space
Aneurysm, CVA
Inferior petrosal sinuses
Drain blood from cavernous sinuses to jugular foramen
Run posteriorly and laterally in groove between petrous portion of temporal bone and basiliar portion of occipital bone
Where is CSF made?
Ventricles of the brain
Product of blood plasma - continuously made
Falx cerebelli
Partially separates the cerebellar hemispheres
Diaphragma sellae
Horizontal sheet of dura over pituitary gland in sella turcica (sphenoid)
Encircles stalk of pituitary
Attachment of dura mater to bones of the floor of the cranium is ______ than it’s attachment to the calvaria
Stronger
Superficial middle cerebral vein
In lateral fissure of the cerebral hemispheres
Drains into sphenoparietal sinus (then cavernous sinuses)
How can headaches be caused by the meninges?
Deformation of the dura mater from distention of the menangial arteries
Changes in pressure of subarachnoid space (lumbar puncture)
Arachnoid villi
Projections of the arachnoid mater into the superior sagittal space
CSF travels into bloodstream through these
Transverse sinuses
Carries blood laterally from the confluence of sinuses - sigmoid sinuses
