what are the three protective layers of the brain
- dura mater
- arachnoid mater
- arachnoid trabeculae
- cerebral artery branch
- pia mater
what is included in the dura mater and what is it
tough fibrous and bridges the crevices and attaches itself to the skull
branches of the middle meningeal artery (this artery is easy to rupture due to the period
what is the arachnoid layer
delicate, sealed bag filled with CSF that bridges the gaps between crevices
where is the cerebral artery branch
its embedded within the Pia mater
what are cisterns
areas filled with CSF
what are the four major cisterns
- superior cistern
- interpeduncular cistern
- cisterna pontis
- cisterna magna (cerebellomedullaris)
what major vascular structure lies within the subarachnoid space
the circle of willis - a berry aneurysm on the circle of willis is a very common cause of subarachnoid haemorrhage
what are denticulate ligaments made of
extensions of pia mater
where does the venous system of the brain lie
subarachnoid space
where do the veins of the brain drain into
the cranial venous sinuses
what is the membrane that separates the two hemispheres and what is the membrane that lies n the posterior aspect of the cerebrum and the superior aspect of the cerebellum
the falx cerebri
tentorium cerebelli
what sinus runs the length of the falx cerebri
the superior sagittal sinus
what sinus runs the length of the tentorium cerebelli
the transverse sinus
where the s.s.s and the t.s meet this is called the
confluence of sinuses
what sinus projects from the confluence of sinus
the straight sinus
what vein branches off the straight sinus
the great cerebral vein, then inferiorly the basal vein and superiorly the internal cerebral vein
Cerebrospinal fluid (CSF)
• Clear colourless fluid which fills the ventricles of the brain surrounds the brain and spinal cord
what are the ventricles of the brain
2x lateral inter ventricular foramen third ventricle cerebral aqueduct fourth ventricle
Formation of CSF
- Formed in the choroid plexus (up to half from blood vessels surrounding the ventricles)
- Core of vascular Sssue (in pia) covered by an epithelium which secretes cerebrospinal fluid
(epithelium differentiated from ependyma – classified as glial)
CSF flows out of ventricle system into
subarachoid sp. via apertures in fourth ventricle through arachnoid granulations
Hydrocephalus is caused by
Due to blocked transport (non-communicaSve), or to overproducSon/ blocked absorpSon of CSF (communicaSve)
resulting in enlarged cranial cavity and dilated ventricles
treated most commonly with a shunt
