Meninges & the Ventricular System Flashcards
What comprise the meninges?
- Pia mater
- Arachnoid mater
- Dura mater
1 has two layers namely __(2)__and __(3)__. These layers are closely united except where?
- Outermost meninx?
- Dura mater
2 layers:
2. Endosteal layer
>Same as periosteum covering surface of the skull bones
- Meningeal layer
>Dura mater proper
>continuous with dura mater of spinal cord
Closely united except in areas where they separate to form the venous sinuses
Meningeal layer septa
1. Sickle-shaped fold of dura mater in the midline between the cerebral hemispheres
- Crescent-shaped fold of dura mater. Roofs over posterior cranial fossa covering the upper surface of the cerebellum supporting the occipital lobes
- Small sickle-shaped fold of dura mater attached to the internal occipital crest. It projects forwards between the two cerebellar hemispheres.
- Small, circular fold of dura mater which forms the roof of the sella turcica; small opening is seen in its center which allows passage of the pituitary stalk
- Falx cerebri
- Tentorium cerebelli
- Falx cerebelli
- Diaphragma sellae
Structure that is a gap in the anterior edge of the tentorium cerebelli which allows passage of the midbrain
Tentorial notch
The dura is innervated by?
Branches of trigeminal (CN V), vagus (CN X) nerves, the first 3 cervical spinal nerves and branches from the sympathetic trunk
Arterial and venous supply of the dura?
Arterial: From the middle meningeal artery, a branch of the maxillary artery from the external carotid artery
Venous: Branches of middle meningeal artery DRAIN INTO the pterygoid venous plexus or sphenoparietal sinus
Dural venous sinuses are located where? Function?
Identify
1. Dural venous sinus that occupies the upper fixed border of the falx cerebri and runs posteriorly. It becomes dilated at the internal occipital protuberance forming the ____? Receives which veins (3)?
- (a) Dural venous sinus that occupies the free lower margins of the falx cerebri. Also runs posteriorly and joins the great cerebral vein at the free margin of the tentorium cerebelli to form another sinus (2b) which will turn left to form which left (2c) sinus?
- Paired structures that begin at the internal occipital protuberance and occupy the attached margin of the tentorium cerebelli. Difference of right from left? Receives which sinuses and veins (4)?
- Direct continuation of #3 which turns forward and inferiorly through the posterior part of which foramen to become continuous with the superior bulb of the IJV.
- Small sinus occupying the attached margin of the falx cerebelli. Begins near the foramen magnum and communicated with the vertebral veins. Drains where?
- Situated in the middle cranial fossa on each side of the body of the sphenoid bone.
B. Which structures (artery and nerve) run through this sinus?
C. Which structures run forward in the lateral wall?
D. How do these two sinuses communicate with each other?
Between layers of the dura mater.
Function: To receive blood from the brain through cerebral veins and receive CSF from the subarachnoid spaces through the arachnoid villi ultimately draining into the IJVs
- Superior sagittal sinus
>Forming the confluence of the sinuses
>Receives: Meningeal, cerebral, diploic veins - (A) Inferior sagittal sinus
(B) Straight sinus
(C) Transverse sinus - Tranverse sinus
>Right: Continuous usually with superior sagittal
>Receives Superior Petrosal sinuses, Inferior cerebral, Cerebellar, Diploic Veins - Sigmoid sinuses
>Jugular foramen - Occipital sinus
>Drains into the sinus confluence - Cavernous sinuses
B. ICA and CN VI
C. CN III, IV; Maxillary and ophthalmic divisions of CN V
D. Through the anterior and posterior intercavernous sinuses
Potential space between the dura and arachnoid mater?
Subdural space
Space between the arachnoid and pia mater? This area is filled with?
What’s special about this place?
Subarachnoid space
- filled with cerebrospinal fluid
- ALL cerebral arteries and veins, as well as cranial nerves lie in this space
Subarachnoid cisterns
- Located between the inferior surface of the cerebellum and roof of the 4th ventricle
- Located between upper clivus and anterior pons
- Cistern located under the splenium of corpus callosum and is continuous anteriorly with the velum interpositum
- Located superior to pituitary gland
- Connects the #4 and #5 wrapping around the midbrain
- Located between the two cerebral peduncles
- Cisterna magna
- Prepontine cistern
- Quadrigeminal cisterm
- Suprasellar cistern
- Ambient cistern
- Interpenduncular cistern
The subarachnoid space extends beyond the lower end of the spinal cord and invests the what? It ends where?
Cauda equina.
Ends at the S2-S3 vertebral level.
The arachnoid projects into the venous sinuses in certain areas forming what? (1) which are most numerous where? (2)
Aggregations of #1 are called (3) whose function is to serve as the site where _ (4) diffuses into the bloodstream
- Arachnoid villi
- Most numerous at the superior sagittal sinus
- Aggregates of arachnoid villi are called arachnoid granulations
- These serve as site where CSF diffuses into the bloodstream
These ventricles communicate with each other through?
- Lateral -> 3rd ventricle
- 3rd ventricle -> 4th ventricle
- Interventricular foramina of Monro
2. Cerebral aqueduct
The ventricles of the brain are developmentally derived from what (1)? It is lined with __(2)__ and filled with __(3)__.
- Cavity of the neural tube
- Lined with ependyma
- CSF
Identify the ventricle
1. Roughly C-shaped cavities divided into a body, anterior, posterior, and inferior horns located in the 4 lobes of the brain & in each cerebral hemisphere.
- Slit-like cleft between thalami.
- Tent-shaped cavity located anterior the cerebellum and posterior to pons and superior half of medulla oblongata.
- Lateral ventricles
- 3rd ventricle
- 4th ventricle
