Dural Venous Sinuses Flashcards
What are the layers of the dura mater?
Periosteal layer and meningeal layer
When do the periosteal layer and meningeal layer separate?
For dural venous sinuses
Whate does the emissary vein drain?
Drains from scalp to dural venous sinus
What is the subdural space?
A POTENTIAL space, can be opened due to bleeding from bridging veins or after an LP due to negative pressure
Where is CSF found?
Subarachnoid space
What is the main artery supply to the brain?
Internal carotid a
How are septa made?
When the meningeal layer of the dura mater separates, comes together, and goes down into the brain
What are septa for?
Stabilization and support
What are the main cranial dural septa?
Falx cerebri, tentorium cerebelli, falx cerebelli, diaphragma sellae
What does the falx cerebri separate?
The two hemispheres of the brain (sagittal plane)
What does the tentorium cerebelli separate?
The cerebellum from the cerebrum (horizontal plane)
Where is the diaphragma sellae?
At the optic chiasm near the pituitary gland
What does the falx cerebelli separate?
The two hemispheres of the cerebellum (sagittal plane)
What is the main arterial supply to the meninges?
Middle meningeal artery
What are the branches of the main arterial supply to the meninges?
Frontal (anterior) and parietal (posterior)
Where does the middle meningeal artery arise?
The maxillary artery
What does the middle meningeal artery split into?
Frontal (anterior) branch and parietal (posterior) branch
What foramen does the middle meningeal artery come out of the skull from?
Foramen spinosum
What nerves innervate the meninges?
V1, V2, V3, and C2/C3 fibers
What is it called when you rupture the middle meningeal a?
Epidural hematoma (because artery is between skull bone and dura mater)
What is the junction of the frontal, parietal, sphenoid, and temporal bones called?
Pterion
What is the lucid interval?
Few hours when blood is slowly filling epidural space before brain is herniated somewhere suddenly
What is it called when you rupture the bridging vein?
Subdural hemorrhage (in “potential space”). Usually acceleration/deceleration injury
What does the bridging vein drain?
From the cortex into the dural venous sinuses
What is it called when an aneurysm ruptures? Why is this bad?
Subarachnoid hemorrhage. Subarachnoid space usually houses CSF and is not prepared to handle blood
How does imaging typically present with epidural hematoma vs subdural hematoma vs subarachnoid hemorrhage?
Epidural hematoma - “lens”- shaped due to the dura being more tightly adhered to suture lines of the skull
Subdural hematoma - “crescent”-shaped
Subarachnoid hemorrhage - “spiderweb”, blood pools deep in brain
What sinus becomes the internal jugular vein?
The sigmoid sinus
Which sinuses help drain the cavernous sinus?
Superior petrosal sinus and inferior petrosal sinus
Which cranial nerves are in the cavernous sinus?
CN III, IV, V1, V2, VI
What gland is located in the cavernous sinus?
Pituitary gland
What are the four parts of the internal carotid artery?
Cervical, petrous, cavernous, cerebral (which eventually gives off circle of willis arteries)
What are clinical signs of cavernous sinus thrombosis?
Periorbital edema, fever, cranial nerve palsies (ex: lateral gaze defect from CN VI damage)
Where is the CSF formed?
The choroid plexus within ventricles of the brain (ependymal cells)
How does CSF drain?
From ventricles to subarachnoid space and then through arachnoid granulations to dural venous sinuses to venous system
What happens if the arachnoid granulations get clogged or don’t work properly?
Hydrocephalus
