Meninges and Dural Folds Flashcards
What are the meninges?
Three membranous layers that surround and protect the brain and spinal cord
What are the layers of the meninges?
Pia
Arachnoid
Dura
What is the pia?
Microscopically thin layer that is adherent to the brain and continuous down the spinal cord
What is the arachnoid?
Soft translucent membrane - continuous down spinal cord
What is the dura?
Tough fibrous membrane that is ‘stuck’ to the skull
What is the subarachnoid space?
Space between pia and arachnoid
What is found in the subarachnoid space?
CSF
Cerebral vessels
What are the layers of the dura?
Periosteal - part against inner table of bone
Meningeal - part adjacent to arachnoid
Where do the layers of the dura separate?
Dural folds
Dural venous sinuses
What are dural venous sinuses?
Spaces that are filled with venous blood created by separation of meningeal and periosteal dura
What are the main dural folds?
Falx cerebri
Tentorium cerebelli
What is the role of dural folds?
Help to stabilise the brain and act as a rigid divider
Where to dural venous sinuses drain into?
Internal jugular vein
What are the main dural venous sinuses?
Superior sagittal sinus Inferior sagittal sinus Straight sinus Transverse sinus Sigmoid sinus
Where do all the dural venous sinuses meet?
Confluence of sinuses
Draw out the dural venous sinuses
See lecture notes
Superior sagittal sinus follows falx cerebri
Inferior sagittal drains into straight
Transverse follows into sigmoid
Sigmoid drains in IJV
Where to cerebral veins drain?
Into dural venous sinuses via bridging veins
In what layers can blood accumulate in the skull?
Extradural
Subdural
Subarachnoid
What is an extradural haemorrhage?
Arterial bleed - typically middle meningeal
Where does blood accumulate in an extradural haemorrhage?
Between bone and dura
Crescent shaped bleed due to continuation of periosteum
What is a subdural haemorrhage?
Venous bleed from bridging vein
Where does blood accumulate in a subdural haemorrhage?
Between dura and arachnoid
What is a subarachnoid haemorrhage?
Arterial bleed secondary to trauma or spontaneous rupture of a blood vessel
Where does blood accumulate in a subarachnoid haemorrhage?
Subarachnoid space
