Cranial Meninges and Intracranial Circulation Flashcards
Within the cranial cavity, the dura matter is composed of which two layers?
Periosteal dura, and meningeal dura
Lines the inner surface of the skull and serves as the periosteum (Endosteum)
PEriosteal Dura
There is normally no space between the periosteal dura and the bone of the skull. However under abnormal circumstances (i.e. bleeding) A space is created there called the
Epidural (or extradural) space
The meningeal dura is fused to the periosteal dura for much of its surface, but in some regions it separates from the periosteal dura to turn internally to form
Dural Septa
The major dural septa include the
Falx cerebri, Falx cerebelli, and Tentorium cerebelli
The Falx cerebri, Falx cerebelli, and Tentorium cerebelli are all composed of only
Meningeal dura
Lies between the two cerebral hemispheres
Falx cerebri
Lies between the two cerebellar hemispheres
Falx ceribelli
Lies between the cerebellum and the occipital lobe of the cerebrum
Tentorium cerebelli
Lie between periosteal dura and the meningeal dura in the regions where the two layers separate
Dural Venous sinuses
Dural venous sinuses are also found within reflections of the
Meningeal dura
Dural sinuses are lined with the same epithelium that is found lining the
Veins of the body
Lies between the periosteal dura and meningeal dura at the root of the falx cerebri
Superior saggital sinus
Lies within a reflection of the meningeal dura at the free edge of the falx cerebri
Inferior saggital sinus
Lies between periosteal dura and meningeal dura at the root of the falx cerebelli
Occipital sinus
Lies within
meningeal dura at the intersection of the falx cerebri and tentorium cerebelli
Straight sinus
Located between periosteal and meningeal dura at the point where the superior sagittal, occipital and straight
sinuses meet
Confluens of sinuses
Lies between periosteal and meningeal dura at the attachment of the
tentorium cerebelli
Transverse sinuses
The anterior continuation of the transverse sinuses
-Drains into the jugular bulb
Sigmoid sinuses
Lie between periosteal and meningeal dura forming the lateral walls of the pituitary fossa`
Cavernous sinuses
Connects the cavernous sinus to the sigmoid sinus
Superior petrosal sinuses
Drains the cavernous sinus into the jugular bulb
Inferior petrosal sinuses
Carry most of the venous drainage from the brain
Dural sinuses
The dural sinuses drain into the
Internal jugular vein
The dural sinuses drain into the internal jugular vein and also communicate with veins of the face, scalp, and neck through
Emissary veins
Do not contain valves
Emissary veins
Since emissary veins do not contain valves, blood can flow in either direction. Thus, these veins can be pathways for the
Spread of infection from superficial regions of the face and scalp into the cranial cavity
Intimately fused to the brain
-Follows the sulci and gyri of the cerebral cortex
Pia matter
Does not enter the sulci. It is adherent to the inner surface of the meningeal dura
Arachnoid matter
Are the dura and arachnoid surfaces fused together?
No
The arachnoid is pressed against the dura by
Cerebrospinal fluid pressure
There is usually no space between the
Dura and arachnoid