Scalp, Meninges, Dural Sinuses Flashcards
Name the layers if the scalp. (superficial to deep)
Skin Connective tissue Epicranial aponeurosis Loose areolar CT (subaponeurotic space) Pericranium (periosteum)
What layer of the scalp act as one (superficial) unit?
Skin
Connective tissue
Epicranial aponeurosis
What is the significance of the single, superficial unit of the scalp?
It can move along the loose areolar tissue that is adhered to the pericranium
What is referred to as the “roof” of the cranial vault?
Calvaria
Along what landmarks does the scalp extend?
Extends from external occipital protuberance and superior nuchal lines TO the supraorbital margins
What layer of the scalp is considered the “danger zone” and why?
Loose areolar CT
Infections, blood, and other stuff can quickly pass through this zone and pass into the cranial cavity
Easy passage due to VALVELESS emissary veins
The dura mater has its own layers. What are they?
Periosteal layer
Meningeal layer
What nerves innervate the dura mater?
CN V (all divisions)
CN IX
CN XII
Where can we find the falx cerebri?
Along the longitudinal fissure between both cerebral hemispheres
What important dural sinuses are associated with flax cerebri?
Superior sagittal sinus
Inferior sagittal sinus
Where can we find the tentorium cerebelli?
Between the occipital lobe of the cerebrum and cerebellum
Its basically the separation of forebrain from hindbrain
What is the tentorial notch?
The opening in the tentorium cerebelli for the brainstem (specifically midbrain)
What are arachnoid granulations?
Small protrusions of the arachnoid mater through the dura mater
Where will we find the largest arachnoid granulations?
Superior sagittal sinus; present in all others too, just not as big
Where is the epidural space in the skull?
It is a potential space between bone and PERIOSTEAL layer of dura mater
In an epidural hemorrhage, what vessel would be the cause of the bleed?
Middle meningeal aa. branches
How does an epidural hematoma appear on CT?
Lens-shaped biconvex
How does a subdural hematoma appear on CT?
Crescent shaped
Where will the blood accumulate in a subdural hematoma?
Between the dura mater and arachnoid mater; which is also a POTENTIAL space
Where will the blood accumulate in a subarachnoid hematoma?
In the subarachnoid space, between arachnoid mater and pia mater AMONG those arachnoid trabeculae
This is an ACTUAL space
What are the contents of the subarachnoid space?
CSF, arteries, veins near surface of brain, and intracranial portions of CNs
What is the common cause of a subarachnoid hematoma/hemorrhage?
Ruptured aneurysm
How does a subdural hematoma appear on CT?
Blood will be seen tracking down into sulci following contour of the pia (bc pia is like the “floor” of subarachnoid space
What are the major dural sinuses?
Superior sagittal, Inferior sagittal Straight Transverse Sigmoid Cavernous Superior petrosal sinuses
How do dural sinuses form?
Via separation of periosteal and meningeal layers of dura mater
What is the significance of dural sinuses?
They allow drainage of blood from the veins of the brain to the internal jugular vein
Majority of sinuses drain to internal jugular vein
True or False:
Dural sinuses have valves to move blood from the brain.
False; dural sinuses are valveless
What is the name of the region where 5 sinuses meet?
The confluence of sinuses
What 5 dural sinuses meet at the confluence of sinuses?
- Superior sagittal
- Straight sinus
- Transverse sinus (bilaterally)
- Occipital sinus
Describe the flow of of the venous return in the dural sinuses.
draw it out
What structures traverse the cavernous sinus?
Internal Carotid a. and CN VI
What structures run in the lateral walls of the cavernous sinus?
CN III, IV, V (opthalmic)
What structure runs deep to the dura in the cavernous sinus area?
CN V (maxillary branch)
Overall, what structures can me damaged if there is a cavernous sinus thrombosis?
ICA
CN III, IV, V(opthalmic & maxillary), VI
What is the significance of the superior petrosal sinus in venous return?
It receives cerebellar veins and inferior cerebral veins and veins from tympanic cavity
True or False:
Cavernous sinuses communicate with one another.
True
What are emissary veins?
Small veins connecting the dural venous sinuses with the veins of the scalp
The superior sagittal sinus receives blood from what veins?
Superior cerebral veins
