Cerebral Vasculature Flashcards
-> Organisation of the nervous system: Compare and contrast the structure of the central, peripheral and autonomic (sympathetic and parasympathetic) nervous systems -> Nervous system disorders: Describe the clinical features and treatment options of central and peripheral nervous system disorders
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?
- 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 (2)?
- Occipital lobe
- Inferior part of the temporal lobe
What does the middle cerebral artery supply (2)?
- Temporal lobes
- Parietal lobes
What does the anterior cerebral artery sypply (2)?
- Frontal lobes
- 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?
- Internal jugular vein
What are the meningeal layers?
- 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 are the four types of haemorrhages?
- Extradural
- Subdural
- Subarachnoid
- Intracerebral
What produces the cerebrospinal fluid?
- Produced by the choroid plexus (modified ependymal cells)
What is the weakest point of the cranial cavity?
- Pterion - Ruptures the middle meningeal artery
Which type of haemorrhage is associated with delayed symptoms?
- Subdural haemorrhage
What are the two types of stroke?
- Ischaemic (Thrombo-emoblic)
- 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 an 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 (5)?
- Age
- Hypertension
- Cardiac disease
- Smoking
- T2DM
What is visual agnosia?
- The inability to recognise
What is prosopagnosia?
- A cognitive disorder of face perception
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 type of pattern is shown on an MRI for an extradural bleed?
- Lemon-shaped bleed
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 types of vessels are implicated in a subdural haemorrhage?
- Cortical veins
What is a subarachnoid haemorrhage?
-
Blood accumulation with the subarachnoid space
- Subarachnoid bleeds typically present at the base of the brain, most often due to aneurysmal ruptures
- 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?
- Intracerebral haemorrhage
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 stroke (3)?
- 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 (4)?
- 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 area
- Wernicke’s area
What are the clinical manifestations for a posterior cerebral artery stroke (2)?
- Visual agnosia (Inability to recognise)
- Prosopagnosia (A cognitive disorder of face perception)
Which topographic region is most likely implicated in a MCA stroke?
- Arm > leg
Identify a suitable diagnosis based on the image.
Subdural
Trauma, can be delayed clinical effects (venous, lower pressure)
Identify a suitable diagnosis based on the image.
Intracerebral
Spontaneous hypertensive
Identify a suitable diagnosis based on the image.
Extradural
Trauma, immediate clinical effects (arterial, high pressure)
Identify a suitable diagnosis based on the image.
Subarachnoid
Ruptured aneurysms
