Cerebral Vasculature Flashcards
What does the brachiocephalic trunk bifurcate into?
Right common carotid artery
Right subclavian artery
What artery supplies the head and neck?
External carotid artery
Which artery supplies the brain?
Internal carotid artery
Where does the internal carotid artery pass through into the cranial cavity?
Carotid canal
Which cranial bone is the carotid canal found in?
The temporal bone
Which arteries do the vertebral arteries arise from?
Subclavian arteries
Where do the vertebral arteries enter into the cranial cavity?
Foramen Magnum
What do the paired vertebral arteries fuse into?
Basilar artery
Which artery connects the posterior and middle cerebral arteries?
Posterior communicating artery
What does the posterior cerebral artery supply?
Occipital lobe and the inferior part of the temporal lobe
Where does the middle cerebral artery supply?
Supplies the temporal and parietal lobes
Where does the anterior cerebral artery sypply?
Frontal lobes and superior medial parietal lobes
Which artery connects the anterior cerebral arteries?
Anterior communicating artery
How is CSF reabsorbed?
Via the arachnoid granules into the superior sagittal sinus
Where does the transverse sinus drain into?
Sigmoid sinus
Where does the sigmoid sinus drain into?
Into the internal jugular vein
What are the meningeal layes?
Dura mater
Arachnoid
Pia mater
What are the two layers of the dura mater?
Periosteal
Meningeal
Which layer is adherent to the inner surface of the bone?
Periosteal dura layer
What produces the cerebrospinal fluid?
Produced by the choroid plexus (modified ependymal cells)
What are the four types of haemorrhages?
Extradural
Subdural
Subarachnoid
Intracerebral
What is an extradural haemorrhage?
A collection of blood that forms between the inner surface of the skull and the outer layer of the dura (endosteal layer)
What are the consequences of an extradural haemorrhage?
Causes an increase in intracranial pressure. Pressure can strip the endosteal layer, away from the cranial cavity.
A rising level of intracranial will eventually cause midline shift and tentorial herniation - compression of brainstem
What is the weakest point of the cranial cavity?
Pterion -Ruptures the middle meningeal artery
What type of pattern is shown on a CT for an extradural bleed?
Lemon-shaped bleed on MRI
What is a subdural haemorrhage?
An accumulation of blood in the subdural space, the potential space between the dura and arachnoid mater of the meninges.
Which type of haemorrhage is associated with delayed symptoms?
Subdural haemorrhage
Which types of vessels are implicated in a subdural haemorrhage?
Cortical veins
What is a subarachnoid haemorrhage?
Subarachnoid bleeds typically present at the base of the brain, most often due to aneurysmal ruptures Blood accumulation with the subarachnoid space.
• Berry aneurysms are arterial swellings usually at the junction of arterial bifurcation.
What type of aneursyms are common in subarachnoid haemorrhage?
Berry Aneursyms
What is an intracerebral haemorrhage?
Intracerebral haemorrhages usually arise from ruptures of an arteriosclerotic small artery that has been weakened predominantly by chronic arterial hypertension.
• Charcot-Bouchard aneurysms more likely to be found in lenticulostriate vessels (Anterior circulation of the Circle of Willis and supplies the basal ganglia). Chronic hypertension can result in cerebral microbleeds.
Which type of haemorrhage is linked with hypertension?
Intra-cerebral haemorrhage
What are the two types of stroke?
Ischaemic (Thrombo-emoblic) and haemorrhagic
What is a transient-ischaemic stroke?
The consequences of a temporary disruption of the circulation to part of the brain due to thrombo-embolic causes
What is cerebral ischaemia?
Lack of sufficient blood supply to nervous tissue resulting in permanent damage if blood flow is not restored quickly. Compromised blood flow leads to anoxia considering there is a reduced availability of respiratory substrate and oxygen for the metabolic cerebral activity.
What is a thrombo-embolic stroke?
The formation of a thrombus elsewhere within circulation can be degenerated into am embolus, being carried within circulation into cerebral arteries. Atherosclerotic debris from the internal carotid artery can further contribute to the development of a thrombo-embolic stroke.
What are the risk factors for a stroke?
Age Hypertension Cardiac disease Smoking Diabetes mellitus
What is the perfusion field for the middle cerebral artery?
The artery supplies a portion of the frontal lobe and the lateral surface of the temporal and parietal lobes
What is the perfusion field for the anterior cerebral artery?
Supplies the para-saggital midline of the brain, perfusion of the occipital fissure
What is the perfusion field for the posterior cerebral artery?
Largely supplies the occipital lobe, in addition to the inferior region of the temporal lobe
What are the symptoms that manifest from an ACA?
Contralateral motor paralysis (leg>arm)
Disturbance of intellect, executive function and judgement (abulia)
Loss of appropriate social behaviour (disinhibition)
Which type of stroke is referred to as a ‘classic stroke’?
Middle cerebral artery stroke
What are the symptoms that manifest from a middle cerebral artery stroke?
Contralateral hemiplegia
Contralateral hemisensory deficits
Hemianopia
Aphasia (In a left-sided lesion)
Which two areas are specifically affected in a left-sided lesion to the middle cerebral artery?
Broca’s and Wernicke’s
What are the clinical manifestations for a posterior cerebral artery stroke?
Visual agnosia (Inability to recognise)
Prosopagnosia (A cognitive disorder of face perception)
What is visual agnosia?
The inability to recognise
What is prosopagnosia?
A cognitive disorder of face perception
Which topographic region is most likely implicated in a MCA stroke?
Arm > leg
