Flashcards in Meninges and Dural Venous Sinuses Deck (22)
What are the 2 layers of the dura mater? Which is continuous with the dura mater of the spinal cord, and which is continuous with the periosteum on outside of skull?
Meningeal layer (dura mater proper)
Endosteal layer is continuous with periosteum on outside of skull through the foramina of the skull
Meningeal layer (dura mater proper) is continuous with the spinal cord
What are the 4 dural septa (or infoldings) which separate regions of brain from each other?
What attaches the falx cerebri anterior and posteriorly, as well as inferiorly?
Connected anteriorly to the inner surface of the skull from the frontal crest and the crista galli.
Connected posteriorly to the internal occipital protuberance
Inferiorly blends with the tentorium cerebelli
What is the gap anteriorly in the tentorium cerebelli? What passes through here?
Called the tentorial notch for passage of midbrain
What partially separates the cerebellar hemispheres?
The falx cerebelli
What forms the roof of the sella turcica?
The diaphragma sellae; contains a small opening in center to allow passage of the pituitary
What are the 6 major venous sinuses?
1. Superior sagittal sinus
2. Inferior sagittal sinus
3. Straight sinus
4. Transverse sinuses
5. Sigmoid sinuses
6. Cavernous sinuses
What venous sinuses meet at the confluens of the sinuses?
Superior, sagittal, straight, occipital, and transverse
Where does the superior sagittal sinus begin anteriorly and end posteriorly?
Begins anteriorly at the foramen cecum and ends posteriorly at the confluens of the sinuses near internal occipital protuberance
Which sinus does the inferior sagittal sinus continue as after union with ____ vein?
The inferior sagittal sinus continues as the straight sinus after union with the great cerebral vein of Galen
What sinus drains the confluens of the sinuses?
The transverse sinuses drain the confluens of the sinuses
What sinus is a direct continuation of the transverse sinus? What does that sinus continue as?
Sigmoid sinus, continues as the internal jugular vein
From which veins/sinuses do the cavernous sinuses receive blood from? Where do they drain to?
Receive blood from:
-Superior and inferior ophthalmic veins
-superior and inferior petrosal sinuses
-Pterygoid venous plexus
What arteries supply the dura?
The middle meningeal artery is the main blood supply (is a branch of the maxillary artery of the external carotid artery
What provides innervation for the anterior cranial fossa?
Meningeal branches of the anterior ethmoidal nerve from the ophthalmic nerve (V1) supply floor and anterior parts of falx cerebri
Tentorial branch supplies the tentorium cerebelli and posterior part of falx cerebri
What provides innervation for the middle cranial fossa?
Supplied medially by meningeal branches of the maxillary nerve (V2)
Supplied laterally by the meningeal branch of the mandibular nerve (V3) (follows distribution of the middle meningeal artery)
What provides innervation for the posterior cranial fossa?
Supplied by meningeal branches of the first 3 cervical nerves
What types of fibers do meningeal nerve branches that supply the dura carry?
They carry sensory neurons (e.g. with headaches, result of these sensory fibers)
Also carry postganglionic sympathetic fibers from superior cervical ganglion
What results if there is infection in any part of the cavernous sinus?
Because there are no valves** in any of these sinuses, an infection in any of the regions that run through the cavernous sinus can spread to the cavernous sinus and elsewhere, causing thrombosis and meningitis (50% mortality)
If this part of the side of the head is struck, what artery may be severed, and what does this result in?
If the pterion region of the head is struck, the middle meningeal artery may be severed, causing an epidural hematoma.
So an epidural is arterial blood*
What causes a subdural hematoma?
Tearing of the superior cerebral veins at the point of entrance to the superior sagittal sinus. May be caused by a blow to the front of back of the head. Blood accumulates in space between dura and arachnoid membrane