Blood Supply, Venous Drainage and Cranial Nerves Flashcards
what are the main 2 sources of blood supply to the brain
vertebral and internal carotid artery
what is the pathway of the vertebral artery
subclavian - vertebral - transverse foramina of C1-C6 - foramen magnum and cranial cavity
what forms the basilar artery
left and right vertebral arteries
what supplies the anterior and middle parts of brain
internal carotid artery
what does the external carotid artery supply
the meninges via the middle meningeal artery
where does the middle meningeal artery run
between the bone and the dura at the pterion
what does the circle of willis supply
anterior, middle and posterior brain
where does the circle of willis lie
around the optic chiasm and pituitary stalk
where does the circle of willis lie
around the optic chiasm and pituitary stalk
where does the basilar artery lie
over the pons
what do the posterior cerebral arteries supply
posterior brain (occipital lobe)
what do the posterior communicating arteries do
communicate with anterior and middle part of circulation in circle of willis
what does the middle cerebral artery supply
the internal capsule via small lenticular striate arteries, temporal lobe, parietal lobe, frontal lobe
what do the anterior cerebral arteries supply
medial side of the cranial hemisphere and anterior part of brain
if there is a stroke in the anterior cerebral artery supplying the front of the brain, what is affected
lower limbs, personality, cant identify objects
if there is a stroke in the middle cerebral artery supplying the temporal, parietal and frontal lobe and internal capsule, what is affected
brocas and wernickes (aphasia), face and upper limb
if there is a stroke in the posterior cerebral artery supplying the occipital lobe what is affected
vision, memory
what are dural venous sinuses
spaces between perisosteal and meningeal layers of dura mater
what occurs in the dural venous sinuses
venous drainage and CSF resorption
once the CSF circulates in the ventricles, what happens to it
goes into subarachnoid space, absorbed through arachnoid granulations and then into superior sagittal sinus
what are the main sinuses
superior sagittal sinus, sigmoid sinus, cavernous sinus, transverse sinus
where does the superior sagittal sinus run
in the falx cerebelli to the back where the falx meets the tentorium cerebelli
where does the superior sagittal sinus split at the posterior aspect of the brain
at the conference of sinuses into left and right transverse sinus
where does the transverse sinus run
within the tentorium cerebelli and along the base of the skull to drain into the jugular foramen
where does all venous drainage go
into the IJV
where does the cavernous sinus run
beside the sellae turcica
why is the blood supply slow in the cavernous sinus
because there are lots of small channels
how does a cavernous sinus thrombosis happen
because the slow blood supply gives the bacteria spread from the danger zone time to multiply
what does a cavernous sinus thrombosis cause
fever and swollen eyes
what causes a cavernous sinus thrombosis
injury/infection of the face/upper teeth
why does an epidural haematoma occur
due to rupture of the middle meningeal artery at pterion, associated with fracture/trauma
which type of haematoma would loss of consciousness be quick and why
epidural haematoma - anterior bleed
what is a subdural haematoma associated with
age as tissues are less sturdy and if there is a fall it can be strong enough to rupture the brains blood vessels
how long does it take to develop symptoms of a subdural haematoma and why
a few weeks as it is a slow bleed because it is venous
what happens in a subarachnoid haemorrhage
one of the arteries within the circle of willis ruptures
what is a subarachnoid haemorrhage associated with
aneurysm
where do subarachnoid haemorrhages occur
where the junction between arteries is - where the arterial wall is weaker so an aneurysm can easily burst in subarachnoid space
where do the olfactory and optic nerves come from
forebrain
what are the 5 main functions that a cranial nerve could have
motor fibres to voluntary muscle
motor fibres to involuntary muscle
general sensation
visceral sensation
special sensation
what does the spinal accessory nerve innervate
SCM and trapqezius
what cranial nerve passes through the nose
1 (olfactory)
what cranial nerve passes to the orbit
optic, occulomotor, trochlear, trigeminal ophthalmic, abducens
what cranial nerve passes to the front of the face
trigeminal maxillary
what cranial nerve passes through the base of the skull
trigeminal mandibular, facial, glossopharyngeal, vagus, accessory, hypoglossal
