Skull Flashcards
what is the Monro-Kellie hypothesis
pressure-volume relationship between volume of CSF, blood, brain tissue and cerebral perfusion pressure (CPP)
what are the layers of the scalp
SCALP Skin Connective Tissue Aponeurosis Loose connective tissue Pericranium
what is the thinnest part of the skull
pterion
what is the pterion
H-shaped
composed of frontal, parietal, temporal and sphenoid bone
what lies behind the pterion
the middle meningeal artery
what are meninges
protective coverings for the brain and spinal cord
what are the layers on meninges of the brain and spinal cord from SUPERFICIAL to DEEP
- Dura mater
- Arachnoid Mater
- Subarachnoid space
- Pia Mater
what is the features of the Dura mater; what is its nerve supply & what does it in enclose
- tough/fibrous
- CN V gives sensory supply
- encloses the dural venous sinuses
what is the function of arachnoid granulation in the arachnoid mater
reabsorbs CSF
what is within the subarachnoid space
CSF
what does the Pia mater do
adheres to the brain and the blood vessels & nerves entering/leaving the brain
what is the tentorium cerebelli
- tough sheet of dura mater “tenting” over the cerebellum
- attaches to the ridges of the petrous temporal bone
what is the dura mater adherent to
internal aspects of all the bones of the skull
what is the falx cerebri
midline structure made of dura mater that separates the right and left cerebral hemispheres
where is the circle of willis located
within the subarachnoid space
what does the circle of willis supply
brainstem
cerebellum
what arteries is the circle of willis comprised of
anterior, middle and posterior cerebral arteries
internal carotid artieries
vertebral arteries
where is CSF produced
choroid plexus of the ventricles
where is CSF reabsorbed into
the dural venous sinuses via arachnoid granulations
what is the circulation of CSF
1 - secreted by the choroid plexus then..
2 - from the R&L Lateral ventricles via the R&L foramina of Monro into…
3 - the 3rd ventricle
4 - then via the cerebral aqueduct into..
5 - the 4th ventricle then…
6 - mainly into the subarachnoid space
7 - then reabsorbed via arachnoid granulations
8 - into the dural venous sinuses
how does CSF get into the 3rd ventricle
via the foramina of Monro
what is hydrocephalus
excessive production, obstruction to flow or inadequate reabsorption leads to an increased CSF volume
what are the three types of haemorrhage in the cranial cavity
Extradural
Subdural
Subarachoid
what is an extradural haemorrhage and what might cause it
- between the bone and the dura
- ruptured middle meningeal artery
- trauma to the pterion
what is a subdural haemorrhage and what might cause it
- separates the dura from the arachnoid
- torn cerebral veins
- falls in the elderly
what is a subarachnoid haemorrhage and what might cause it
- into the CSF of the subarachnoid space
- ruptured Circle of wIllis (‘berry’) aneurysm
- congenital aneursym
what does an epidural needle have to pass through
- supraligaments
- interspinous ligaments
- ligamentum flavum
- epidural space (fat & veins)
(this is where the epidural catheter stops at and the lumbar puncture needle continues) - dura mater
- arachnoid mater
- subarachnoid space
when should a LP never be preformed
raised ICP
where is a LP normally preformed
L3/4 interspace
what is the cauda equina compromised of
L2-Co spinal nerve roots
where does the subarachnoid space end
S2
