Dural Sinuses, Meninges, and Vasculature Flashcards
What are the cranial meninges made of?
What is the purpose of them?
Dense regular CT
Separate soft tissue of brain from bones of cranium
Enclose and protect blood vessels supply brain
Contain and circulate CSF
FORM some of the veins that drain blood
What are the layers of cranial meninges from superficial to deep?
Dura
Arachnoid
Pia
What are the two layers of dura mater?
Periosteal
Meningeal
What is below the arachnoid mater?
Subarachnoid space (between arachnoid mater and pia mater)
What is contained in Pia mater?
Contains cerebral a.
What is the arterial supply to the meninges?
Middle meningeal a.
Frontal and parietal Branch
What does middle meningeal go thru after coming off of maxillary a.?
Foramen spinosum
What is the innervation of the meninges?
V1 - ethmoidal n., tentorial n.
V2- meningeal branch
V3 - meningeal branches
Cervical spinal ns. (C2, 3) - floor of posterior cranial fossa
What are the characteristics of the dura mater?
Most Superficial
Toughest and strongest membrane
2 fibrous layers
What forms dural venous sinuses?
Separation of periosteal and meningeal layers
When is a subdural space created? and where?
When something goes wrong, as in a bleeding bridging v. (Subdural hematoma)
Space b/w dura mater and arachnoid
What is arachnoid mater made of?
Arachnoid traveculae (a delicate web of collage and elastic fibers)
What is deep to arachnoid mater? What is here?
Subarachnoid space
CSF
What does pia mater do?
Tightly adheres to brain and follows every contour of the brain surface
What makes a septa? What is a septa?
What are the 4 septa?
Septa: flat partition into cranial cavity Separating specific parts of brain
Made from extension of meningeal layer of dura mater
Falx cerebri; tentorium cerebelli; falx cerebelli; diaphragma sellae
What’s purpose of falx cerebri?
Separates two hemispheres of cerebrum
What’s purpose of falx cerebelli?
Separates two hemispheres of cerebellum
What’s purpose of tentorium cerebelli?
Separates cerebrum from cerebellum
What’s purpose of diaphragma sellae? Where is it?
What sinus is here?
Superior to hypophyseal fossa of sphenoid bone and pituitary gland
Attaches to anterior and posteiror clinoid processes
Opening in middle for passage of pituitary infundibulum
Cavernous sinus
What is found within the septa?
Dural venous sinuses
What are the dural venous sinuses?
Superior and inferior sagittal sinuses
Straight sinus
Sigmoid sinus
Transverse sinus
What happens during an epidural hematoma?
How do you get one?
How does it present?
how does it look on a CT?
Ruptured middle meningeal artery
If you get hit in side of head at pterion point
With a lucid interval where blood slowly fills up space and with brain herniating out
“Lens”
What happens during an subdural hematoma?
How do you get one?
How does it present?
how does it look on a CT?
Rupture briding v.
Acceleration/deceleration injury
Shaken baby syndrome
Crescent shaped
What happens during an Subachanoid hemorrhage?
How do you get one?
How does it present?
how does it look on a CT?
Who is predisposed to it?
Ruptured aneurysm on cerebral a.
Fills subarachnoid space
“The worst headache of my life”
Can even see it during lumbar puncture if there is blood in CSF
Spiderweb on CT
Postmenopausal women and people w/ hypertension
Contributing veins to cavernous sinus? What does this allow for?
Superior opthalmic v.
Inferior ophthalmic v.
Facial v. (Incl. angular v.)
Allow for an infection in the front of the face to spread back
What helps drains the cavernous sinus?
Superior petrosal
Inferior petrosal sinus: Goes from cavernous to sigmoid
What is the associated Neurovascular strucutre in the cavernous sinus?
ICA
CN 3, 4, v1, V2, 6
Diaphragm sellae
What is a Cavernous Sinus Thrombosis?
Clinically presents with?
Compress CN3, 4, V1, V2 and 6
(6 is mostly affected bc of its proximity)
High fever, periorbital edema, CN palsies, decreased visual acuity
What are the 4 parts of the ICA?
Which part will give off cerebral arteries? What do they form?
Cervical, petrosal, cavernous, and cerebral
Cerebral gives off cerebral As. In the Circle of Willis
What is the CSF?
Clear colorless liquids that circulate sin ventricles and subarachnoid space
What are the functions of CSF?
Buoyancy
Protection
Environmental stability
What is CSF formed by and produced by?
Formed by choroid plexus in each ventricle
Produced by ependymal cells
Where do ependymal cells originate from and what do they do?
Originate from blood plasma
Secrete and produce CSF
What is the makeup of CSF?
Similar to blood plasma but has greater amount of Na, H, Ca
Less K
What doe arachnoid granulation do?
Help csf flow to dural venous sinus
What happens to the arachnoid granulation if there is a subarachnoid hemorrage?
What is this called?
Blood is flowing into subarachnoid space
Cannot be filtered out thru arachnoid granulation (will damage granulation, causes them to fibrose, and clog whole system)
Causes enlargement of ventricle and compression of brain
= Hydrocephalus
What is the danger triangle?
What is this implicated in?
Triangular area from upper lip to the bridge of nose
Thrombophlebitis of facial v.
Facial v. Makes connection w/ cavernous sinus and could allow an infection of the face to spread to cavernous sinus and pterygoid venous plexus
Facial v. Has no valves so blood can go backwards and enter cavernous sinus
