Meninges of the brain Flashcards
Name the 3 meninges[protective membranes] of the brain.
Dura mater
Arachnoid mater
Pia mater
What does each meninge do?
• Dura Mater : durable, lines the brain • Arachnoid Mater : intervenes between dura & pia mater • Pia Mater : adherent to brain surface
Describe the dura mater.
The dura mater is the Outer, durable, double
layered membrane
Endosteal layer of dura mater :
outer,
adherent to bone
Meningeal layer of dura mater :
inner,
splits to enclose dural
venous sinuses
What does the meningeal layer form?
The dura mater - meningeal layer forms partitions
Name and state the location of the partitions.
• Falx cerebri Between cerebral hemispheres • Falx cerebelli Between cerebellar hemispheres • Tentorium cerebelli • Between cerebrum & cerebellum • Diaphragm sella
Describe the falx cerebelli.
The falx cerebelli has and it is :
• Sickle-like shape
• Strong, arched process
The falx cerebelli is a small triangular process
Where does the flax cerebelli lie?
The falx cerebelli lies inferior to the tentorium
cerebelli in posterior cranial
fossa
Describe the tentorium cerebelli.
The tentorium cerebelli is an arched lamina and its anterior border is free and concave
What does the tentorium cerebelli cover?
The tentorium cerebelli covers the superior surface of
cerebellum
What does the tentorium cerebelli support ?
The tentorium cerebelli supports the occipital lobes of the brain
What does the tentorium cerebelli bound?
The tentorium cerebelli bounds a large oval opening : for
cerebral peduncles
Describe the diaphragm sella?
The diaphragm sella is
- The Smallest dural infolding
- A circular sheet of dura mater
Where is the diaphragm sella suspended?
The diaphragm sella is suspended between the clinoid
processes
What does the diaphragm sella form?
Forms roof over hypophysial
fossa
What does the diaphragm sella cover?
Covers the pituitary gland
What does the small central opening of the diaphragm sella transmit?
The Small central opening
transmits infundibulum
Where is the endosteal layer of dura mater found?
Found around margins of
every foramen in skull
How does the endosteal layer lie with regards to the periosteum?
Lies in continuity with
periosteum on outer surface
of cranial bones
Describe the arachnoid mater.
•Delicate membrane
•Thin & transparent
*Non vascular
What does the arachnoid mater do?
Invests brain loosely
•Does NOT dip into sulci nor into
fissures
Where does the arachnoid mater lie?
•Lies between pia mater (internally)
& dura mater (externally)
What is the arachnoid mater supported by?
The arachnoid mater is supported by fibrous trabeculae
What is the subarachnoid space?
The Interval between arachnoid&
pia mater
What is the subarachnoid space occupied by?
The subarachnoid space is occupied by spongy tissue
consisting of trabeculae of
delicate connective tissue
What is the pia mater?
The pia mater is a vascular membrane
What does the pia mater invest?
The pia mater invests the entire surface of the brain
What does the pia mater form?
The pia mater forms the tela choroidea and choroid plexus
What does the pia mater consist of?
The pia mater consists of minute plexus of
blood vessels
What is pia mater held together by?
Pia mater is held together by extremely fine areolar tissue
What is the definition of dural venous sinuses?
- Channels within dura mater
- Often triangular in section
- Function as veins- draining brain
What does the venous flow tend to be?
- anterior to posterior
- posterior and downward
- From midline outwards
Describe the Venous drainage of hemispheres :
Does not follow arterial pattern
• Cortical veins travel superficially in arachnoid
mater
• Blood usually flows into nearest available venous sinus
DURAL VENOUS SINUSES:UNPAIRED
Unpaired sinuses:
(median plane)
- Superior sagittal
- Inferior sagittal
- Straight
- Confluence
DURAL VENOUS SINUSES:PAIRED
- Inferior Petrosal
- Cavernous
- Sigmoid
- Superior Petrosal
- Transverse
DURAL VENOUS SINUSES: RELATION TO
TENTORIUM
• Straight sinus • Transverse sinus • Superior petrosal sinus • Cavernous sinus
