Internal Skull and Dural Sinuses Flashcards
What are the boundary points for separatig the interior skull into superior and inferior segments? What are the names of these structures, indicated by the image?
Frontal crest to right above the external occiptial protuberance
Name the structures indicated in the image as well as their boundaries.
- Between frontal and middle fossa:
- posterior border of the lesser wing of the sphenoid
- anterior clinoid processes
- anterior border of the prechiasmatic sulcus
- Between middle and posterior fossa
- superior ridge of the petrous part of the temporal bone
Which meningeal layer is the thinnest and adheres directly to the brain? Describe this layer’s level of vascularization.
Pia mater
highly vascularized by a network of fine blood vessels
What is the name of the second deepest meningial layer? What is the name of the space between this layer and the pia mater? What is this layer’s level of vascularization?
What is the name for the projections where CFS is reabsorbed into the dural venous sinuses?
Arachnoid mater
subarachnoid space (filled w/ CSF)
avascular
Arachnoid granulations
What causes the granular fovea on the cranial vault?
When the arachnoid granulations are very tall and create little divits on the cranium
What layer of the meninges is most superficial? What are its two layers?
Dura mater
- periosteal dura: lines the periosteum of the cranium
- meningeal dura: lines arachnoid mater
What is the name for the 2 layers of meningeal dura that divide cranial cavity into parts?
What is the name for the valve-less space between dura where CSF is reabsorbed inot venous system?
Dural infolding
Dural venous sinus
Identify the shown dural infoldings. Name their attachment points and their general shape.
- Falx cerebi (sickle shaped)
- Attacments
- crest galli
- frontal crest
- sagital sulcus
- internal occipital protuberance
- continuous with tentorium cerebelli (separates R & L) hemispheres of cerebrum
- Attacments
- Tentorium cerebelli (crescent shaped)
- Attachments
- anterior clinoid process
- superior ridge of petrous temporal bone
- posterior clinoid process
- transverse sulcus
- forms “tent” w/ falx cerebi
- separates cerebrum from cerebellum
- Attachments
- Falx cerebelli (sickle shaped0
- Attachments
- inferior to internal occipital protuberance
- internal occipital crest
- inferior to tentorium cerebelli/ partially separates hemispheres of cerebellum
- Attachments
- Diaphragma sellae (horizonal sheet)
- covering hypophyseal fossa– has an apeture for stalk of pituitary
- Attachment
- posterior clinoid process
- anterior clinoid process
Which dural infolding creates the structure through which the brain stem passs? What is the name of this structure?
tenrotium cerebelli, b/c it is unattached at the anterior border forms the tentorial notch, through which the brainstem passes
What is the arterial supply of the dura?
meningeal arteries
middle meningeal makes grooves in temporal bone
Identify the nerves innervating the dura mater indicated on the provided image
What are the two potential spaces contained in the dura?
extradural and subdural spaces
they exist as a restult of pathology or trauma
Name the structure indicated on the image.
Position?
Blood supply?
Drains to?
Superior sagittal sinus
- midline; superior border of falx cerebri
- receives blood
- frontal, parietal, occipital lobest
- drains into confluence of sinuses
Name the structure indicated on the image.
Position?
Blood supply?
Drains to?
Inferior sagittal sinus
- midline; inferior free border of falx cerebri
- receies blood
- veins along falx cerebri
- cerebral hemispheres of brain
- Drains into
- straing sinus
Name the structure indicated on the image.
Position?
Blood supply?
Drains to?
Striaght sinus
- midline; at intersection of falx cerebri & tentorium cerebelli
- Receives blood
- inferior saggial sinus & great cerebral vein
- Drains into
- confluence of sinuses & left transverse sinus
Name the structure indicated on the image.
Position?
Blood supply?
Drains to?
Occipital sinus
- midline; along posterior border of falx cerebelli
- receives blood
- internal vertebral plexus (inferior to occipital sinus)
- drains into
- confluence of sinuses
Name the structure indicated on the image.
Position?
Blood supply?
Drains to?
Confluence of sinuses
- midline dilation at internal occipital protuberance
- receives blood from
- superior sagittal, straight & occipital sinuses
- Drains into
- transverse sinus
Name the structure indicated on the image.
Position?
Blood supply?
Drains to?
Transverse sinus
- Bilateral; in transverse sulcus
- Receives blood from
- confluence of sinuses, straight sinug & veings from temporal & occipital lobe of brain
- Drains into
- sigmoid sinus with superior petrosal
Name the structure indicated on the image.
Position?
Blood supply?
Drains to?
Superior petrosal sinus
- bilateral; on superior ridge of petrous temoral
- receivs blood from
- cerebela & brainstem veings, cavernous sinus
- drains into
- merges with transverse sinus to form sigmoid sinus
Name the structure indicated on the image.
Position?
Blood supply?
Drains to?
Inferior petrosal sinus
- bilateral; in groove between petrous tempora & basilar part f occipital bone
- received blood from
- cavernous sinus
- drains into
- merges with sigmoid sinus to form internal jugular vein
Name the structure indicated on the image.
Position?
Blood supply?
Drains to?
Sphenoparietal sinus
- bilateral; inconstant; on posterior margon of lesser wing of sphenoid
- receives blood
- variety of small veins from brain
- drains into
- cavernous sinus
Name the structure indicated on the image and the neurovasculature found within.
Position?
Blood supply?
Drains to?
Cavernous sinus
- Bilateral; very large venous plexus from superior orbital fissure to apex of petrous temporal; lateral to sella turcica; connected by intercavernous sinuses
- Receives blood from
- superior & inferior opthalmic veins, superficial middle cerebral, & inferior cerebral veings & sphenoparietal sinus
- drains into
- superior and inferior petrosal sinuses
Name the structure indicated on the image.
Position?
Blood supply?
Drains to?
Sigmoid sinus (S shaped)
- bilaeal; in the sigmoid sulcus
- received blood from
- transverese & superior petrsal sinuses
- drains into
- merges with inferior petrosal sinus to form internal jugular vein
Name the bone, foramina, contents and through which structes it allows passage.
- cribiform foramina of the ethmoid bone
- multiple small foramina on the ethmoid plate
- contains
- small nerve fibers from olfactory nerve
- passage between anterior cranial fossal & nasal cavity
Name the bone, foramina, contents and through which structes it allows passage.
- Foramen secum of the frontal bone
- stays open only in 1% of adults
- contains:
- frontal emissary vein (inection path from nasal cavity ot brain meninges)
- passage
- anterior cranial fossa & nasa cavity
Name the bone, foramina, contents and through which structes it allows passage.
- Optic canal of sphenoid
- angled canal in lesser wing of sphenoid – medial to superiof orbital fissur
- contains
- optic nerve (II)
- opthalmic artery (internal carotid branch)
- passage between middle cranial fossa & orbit
Name the bone, foramina, contents and through which structes it allows passage.
Superior orbital fissue of the sphenoid
- uneven gap btw lesser & greater wings of sphenoid
- dura mater divides it into multiple openings
- Contents:
- oculomotor nerve (III)
- trochlear nerve (IV)
- abducens (VI)
- Superior opthalmic vein
- opthalmic nerve (V1)
- Passage between middle crainal fossa & orbit
Identify the contents of the superior orbital fissure
Name the bone, foramina, contents and through which strucures it allows passage.
Foramen rotundum of the sphenoid
- anterior-posterior foramen, found between medial margin of superior orbital fissure & foramen ovale
- contents
- maxillary nerve (V2)
- passage
- between cranial fossa & pterygopalatine fossa
Name the bone, foramina, contents and through which structes it allows passage.
Foramen ovale of sphenoid
- oval shaped foramen posterolateral to foramen rotundum, anterior to trigeminal impression
- contains
- mandibular nerve (V3)
- lesser petrosal nerve
- accessory middle meningeal artery (variable)
- Passage
- middle cranial fozza & infratemporal fossa
Name the bone, foramina, contents and through which structes it allows passage.
Foramen spinosum of the sphenoid
- small foramen posterolateral to foramen ovale
- contains
- middle meningeal artery and vein
- passage
- between middle cranial fossa & infratemporal fossa
Name the bone, foramina, contents and through which structes it allows passage.
Carotid canal of the temporal bone
- L shaped canal, 2 openings:
- external medial to styloid process
- Internal: medial & anterior to external opening
- contains
- internal carotid artery
- passage between middle cranial fossa & neck
Name the bone, foramina, contents and through which structes it allows passage.
Temporal lacerum of the temporal, occipital & sphenoid bones
- irregular shaped gap inferior to carotid canal interal opening
- contains
- fibrocartilage & small nerves and vessels
- passage
- middle cranial fossa & neck
Name the bone, foramina, contents and through which structes it allows passage.
Internal acoustic meatus of the temporal bone
- passageway with opening in posteior of petrous temporal
- contains
- facial n (VII) then to stylomastoid foramen
- vestibulocochlear n (VII)
- labyrinthine a & v
- passage
- between posterior cranial fossa & ear
Name the bone, foramina, contents and through which structes it allows passage.
Foramen magnum of the occipital bone
- largest foramen; posterior to clivus
- contains
- medulla of brain (becomes spinal cord)
- vertebral arteries
- spinal roots of accessory nerve (XI)
- passage between posterior cranial fossa & neck
Name the bone, foramina, contents and through which structes it allows passage.
Hypoglossal canal of occipital bone
- canal superior to anterolateral margin of foramen magnum
- contains
- hypoglossal nerve (XII)
- meningeal branch of ascendign paryngeal artery
- passage
- between posterior vrainial fossa & neck
Name the bone, foramina, contents and through which structes it allows passage.
Jugular foramen of temporal and occipital bones
- irregular opening between petrous temporal & occipital
- dura mater divides into multiple openings
- contains
- internal jugular vein (IJV)
- glossopharyngeal n (IX)
- vagus (X)
- accessory n (XI)
- passage
- posterior cranial fossa & neck
