Meninges and Sinuses Flashcards
Periosteal dura:
- lines the inner surface of the skull and serves as the periosteum.
- meningeal dura fuses to the periosteal dura.
Within the cranial cavity the dura mater is composed of two layers:
- periosteal dura (attached to skull)
- meningeal dura (fused to periosteal dura)
Epidural space in the cranial cavity:
- between the periosteal dura and the skull.
- not normally present, created under abnormal conditions (e.g. bleeding into this plane).
In both the cranial cavity and the vertebral canal, the the arachnoid is pressed against the dura via:
- the pressure of the cerebrospinal fluid
Dural septa:
- regions where the meningeal dura is not fused to the periosteal dura and separates from the periosteal dura to turn internally to form dural septa.
What artery is sandwiched between the periosteal dura and the skull, and is also responsible for the “arterial grooves” on the inner skull?
middle meningeal artery
Shearing a middle meningeal artery may lead to what kind of hematoma?
- epidural
- between the periosteal dura and the skull
Falx cerebri location:
- lies between the two cerebral hemispheres
- a meningeal dura dural septum
Falx cerebelli location:
- lies between the two cerebellar hemispheres
- a meningeal dura dural septum
Tentorium cerebelli location:
- lies between the cerebellum and the occipital lobe of the cerebrum.
- a meningeal dura dural septum.
Dural venous sinuses structure and location:
- lined with the same epithelium that is found lining the veins of the body.
- between periosteal dura and meningeal dura where the two layers separate.
- within reflections of the meningeal dura.
Dural sinuses function:
- carry most of venous drainage from brain.
- communicate with veins of the face, scalp and neck through emissary veins.
- drain into the internal jugular vein
Straight sinus location:
- within meningeal dura at the intersection of the falx cerebri and tentorium cerebelli
Transverse sinuses location:
- between periosteal and meningeal dura at the attachment of the tentorium cerebelli
Confluens of sinuses location:
- between periosteal and meningeal dura at the point where the superior sagittal, occipital and straight sinuses meet
Emissary veins:
- veins that connect the veins of superficial regions of the face and scalp to the dural sinuses
- no valves; blood flows via pressure gradient
What veins can be pathways for the spread of infection from superficial regions of the face and scalp into the cranial cavity?
emissary veins
Cortical (Bridging) Veins:
- carry blood from the brain to the superior sagittal sinus.
- can shear and lead to subdural hemotoma
How do Cortical (Bridging) Veins shear?
- superior sagittal sinus is formed from meningeal dura, it does not move with the brain.
- Cortical (Bridging) Veins are tightly bound to the dura, but are not encased in any dura elswhere and move with the brain.
- Large brain movements will cause Cortical (Bridging) Vein shearing.
Superior sagittal sinus location:
- between the periosteal dura and meningeal dura at the root of the falx cerebri
Inferior sagittal sinus location:
- within a reflection of the meningeal dura at the free edge of the falx cerebri
Occipital sinus location:
- between periosteal dura and meningeal dura at the root of the falx cerebelli
Sigmoid sinuses location:
- the anterior continuation of the transverse sinuses, drains into
- the jugular bulb
Cavernous sinuses location:
- between periosteal and meningeal dura forming the lateral walls of the pituitary fossa
Superior petrosal sinuses location:
- connects the cavernous sinus to the sigmoid sinus
Inferior petrosal sinuses location:
- drains the cavernous sinus into the jugular bulb
Blood flow through the superior sagittal sinus, inferior sagittal sinus, straight sinus, and occipital sinus is all in what direction?
anterior to posterior
Where do all of the superior sagittal, occipital and straight sinuses converge?
confluens of sinuses
What vein drains into the cavernous sinus?
- superior opthalmic vein
- emissary vein - has superficial facial branches
Contents of the cavernous sinus:
- trabeculae
- pituitary gland
- nerves
- arteries
What causes blood flow to be slower in the cavernous sinus?
- trabeculae
- may predispose someone to clotting and/or infection
