Cranial cavity Flashcards
Describe the three layers of the meninges?
Dura mater: outer, tough, fibrous
Arachnoid mater: More delicate, fibrous
Pia mater: Thin layer
What are each of the three layers of the meninges connected to?
Dura mater: Attached to skull
Arachnoid mater: Lines inner of dura
Pia mater: Lines brain tissue
Describe the spaces created by each of the three meninges?
Epidural space: between dura and skull, potential space
Subdural space: between dura and arachnoid, potential space
Subarachnoid space: between arachnoid and pia, occupied by CSF
What can accumulate in the epidural space and when?
Blood collects here when meningeal artery ruptures
What occupies the subarachnoid space?
CSF
What can accumulate in the subdural space and when?
Blood collects here as a result of venous bleeding
List the dural petitions that project into the cranial cavity?
Falx cerebri
Tentorium cerebelli
Falx cerebelli
Diaphragma sellae
How far into the brain do the dural petitions project into the cranial cavity?
Not all the way; don’t cut the brain into component parts
What is the purpose of the dural petitions?
Lodge into the brain partway and restrict rotatory displacement of the brain
Describe the shape of the falx cerebri?
Sickle shaped
Where does the falx cerebri lie?
In midline between the two hemispheres
Describe the attachments of the falx cerebri?
Attaches to inside of skull, immediately along line of sagittal suture Pegs to crista galli anteriorly Attaches posteriorly to internal aspect of occipital protuberance
Describe the shape of the tentorium cerebelli?
Crescent shaped, tented upwards
Where does the tentorium cerebelli lie?
Roofs over posterior cranial fossa, between cerebral hemispheres above and cerebllum below
Where does the falx cerebelli lie?
Between cerebellar hemispheres, beneatch tentorium cerebelli
Describe the orientation of the falx cerebelli?
Vertical
Where does the diaphragma sellae lie?
Roofs over the sella turcica (pituitary) Lines internal aspect of sphenoid bone and goes across pit
How are the projections of the meninges formed?
Dura is a double layered structure; layers are usually stuck together Projections are formed when the inner layer separates from the outer layer, and meets with the inner layer from the other side