Dural Sinuses, Meninges, and Vasculature Flashcards
What are the basic features of dura matter?
Tough membrane of two fibrous layers:
- periosteal: more superficial, attaches to the periosteum of cranial bones
- meningeal: deeper layer
Strongest of the meninges
What happens in areas where the meningeal and periosteal layers of the dura matter separate?
Form large blood-filled spaces called dura venous sinuses
Where does the emissary v. travel?
From the scalp to the dural venous sinus
Where does the bridging v. travel?
from the cortex to the dural venous sinus
Where is arachnoid matter found? What are its structural characteristics
Immediately internal to the dura matter
Delicate web of collagen elastic fibers= arachnoid trabeculae
What is the subdural space?
A POTENTIAL space between the arachnoid and dura matter
What can cause you to see the subdural space?
Bleeding from the bridging vein which then bleeds into the subdural space
Following a lumbar puncture, when you pull out fluid it creates a negative pressure creating space
What is found in the subarachnoid space?
Cerebral spinal fluid
What artery can be found in the subarachnoid? Where does this come from?
Cerebral arteries
Internal carotid –> circle of willis –> cerebral arteries
What can cause you/put you at risk for having an aneurysm in a cerebral artery?
Polycystic kidney disease
Elhers Danlos
Post meopause women: less estrogen –> less cartilage –> weaker blood vessels
Hypertension
AKA anything that weakens your blood vessels
What is the unique characteristic of Pia matter in comparison to the other meningeal layers?
It is the only layer that follows every contour of the brain, thin connective tissue that adheres tightly to brain
What is a cranial dura septa? What is contained in these septa?
An extension of the meningeal layer of the dural matter deep into the cranial cavity which provides stabilization and support
Dural venous sinuses
Where are the four locations of the cranial dural septa? What do they divide?
Falx cerebri (negative mohawk): sagital, separates 2 hemispheres
Tentorium cerebelli: horizontal, separates cerebellum and cerebrum
Falx cerebelli: sagital, separates cerebellum
Diaphragm sellae: overlies pituitary gland, cavernous sinuous
What is the main arterial supply of the meninges? Where does it branch from? What does it pass through?
The middle meningeal artery
external carotid –> maxillary artery –> middle meningeal artery
foramen spinosum
What happens when you haver a ruptured middle meningeal artery?
Epidural hematoma
Symptoms: hit in side of head at first fell okay then blood pools up and reach threshold and brain can’t take it so herniation
Why is rupturing of the middle meningeal artery a common trauma? What does this look like on a scan?
It passes under the Pterion which is a junction of the frontal, parietal, spehnoid, and temporal bones that has a thinner skull
Convex lens
What happens when you rupture a bridging vein? How can this happen? What does it look like on a scan?
Subdural hemorrhage
Old person in an acceleration deceleration accident ie car crash, fall
Shaking baby syndrome
Crescent
What is located in the cavernous sinus?
Oculomotor N. Trochlear N. Abducent N. Trigeminal N. (only ophthalmic and maxillary branches) Internal Carotid A. Pituatary Gland Diapghragma Sellae Infundibulum
What are the 4 parts of the internal carotid artery? How does it travel?
Cervical
Petrous
Cavernous
Cerebral
Up and anteromedially
What can happen when you have cavernous sinus thrombosis?
High fever
Preorbital edema and chemosis (conjunctival edema)
Cranial nerve palsy: most common is CN VI, can’t gaze one eye laterally
Decreased visual acuity
What forms cerebrospinal fluid? What are the cells that secrete it?
Choroid plexus of each ventricle
Ependymal cells (originate from blood plasma but have less potassium)
What is the role of the arachnoid granulation?
Helps flow of CSF from subarachnoid space into venous system
granulation –> dural sinus –> internal jugular vein
How does hydocephalis occur?
Blood in subarachnoid space, arachnoid granulation is not ready because deals with CSF –> fibrosis of arachnoid granulation -> CSF keeps being produced but nowhere to go –> enlargement of ventricles
