The meninges Flashcards
Name the three layers of meninges
- the dura mater,
- arachnoid mater
- pia mater.
Two major functions of meninges
Provide a supportive framework for the cerebral and cranial vasculature.
Acting with cerebrospinal fluid to protect the CNS from mechanical damage.
clinical relevance of meninges
The meninges are often involved cerebral pathology, as a common site of infection (meningitis), and intracranial bleeds.
The dura matter contains which two connective sheets?
Periosteal layer – lines the inner surface of the bones of the cranium.
Meningeal layer – deep to the periosteal layer inside the cranial cavity. It is the only layer present in the vertebral column.
Dural venous sinuses are located where?
Between the periosteal layer and the meningeal layer
The function of dural sinuses
They are responsible for the venous vasculature of the cranium, draining into the internal jugular veins.
List the two main dural reflections?
The two main dural reflections are the falx cerebri and the tentorium cerebelli
The function of the tentorium cerebelli
the tentorium cerebelli divides the cranial cavity into supratentorial and infratentorial compartments.
Describe the blood supply and venous drainage of the dura matter
The dura mater receives its own blood supply – primarily from the middle meningeal artery and vein.
Describe the innervation of the dura matter
It is innervated by the trigeminal nerve (V1, V2 and V3).
Name the two types of hematomas involving dura matter
Extradural hematoma
Subdural hematoma
Descibe an extradural hematoma
Extradural – arterial blood collects between the skull and periosteal layer of the dura. The causative vessel is usually the middle meningeal artery, tearing as a consequence of brain trauma.
Describe a subdural hematoma
Subdural – venous blood collects between the dura and the arachnoid mater. It results from damage to cerebral veins as they empty into the dural venous sinuses.
Explain the importance of the sub-arachnoid space
It contains cerebrospinal fluid, which acts to cushion the brain.
Explain the importance of arachnoid granulations
Small projections of arachnoid mater into the dura (known as arachnoid granulations) allow CSF to re-enter the circulation via the dural venous sinuses.
