16.4 Blood Supply Flashcards
What is the Circle of Willis?
- It is the joining area of several arteries at the inferior side of the brain.
- This is due to the anterior and posterior communicating arteries linking vessels derived from the internal carotid and vertebro-basilar systems.
Where is the Circle of Willis found?
It encloses the optic chiasm.
Label this.
What are the arterial pulse points you need to know.
*Carotid
*Facial
*Superficial temporal
Which sinus is the internal carotid artery related to and how?
- The cavernous sinus
- The ICA passes through the cavernous sinus
What event is the Circle of Willis commonly related to?
Subarachnoid haemorrhage:
- Aneurysms associated with subarachnoid hemorrhages tend to occur in a circle of arteries that supply blood to the brain.
- These are known as the circle of Willis.
- In some people, a congenital anomaly leads to weak and thin blood vessel walls, increasing the risk of an aneurysm.
What event is the middle meningeal artery commonly associated with?
Extradural haemorrhage:
- This tends to occur at the PTERION -> This is the point at which multiple bones join
Which sinus is the internal carotid artery related to and how?
- The cavernous sinus
- The ICA passes through the cavernous sinus
What are the consequences of ACA syndrome?
Anterior cerebral artery syndrome.
- Contralateral leg weakness
- Executive dysfunction/ abulia
What is the consequence of L MCA syndrome?
Left middle cerebral artery syndrome
What is the consequence of Top of the basilar/ Thalmic perforations?
What are the consequences of Mid-basilar stroke?
What are the consequences of cerebellar stroke?
What are the consequences of PCA syndrome?
Posterior cerebral artery syndrome
What are the consequences of R MCA syndrome?
Right middle cerebral artery syndrome
What is this vein?
- Superior sagittal sinus
What is this vein?
- Great cerebral vein
What is this vein?
- Transverse sinus
What is this vein?
- Sigmoid sinus
What is this vein?
- Internal jugular vein
What is this vain?
*Cavernous sinus
Identify the artery marked by the arrow labelled 1:
- Anterior cerebral
- Basilar
- Internal carotid
- Middle cerebral
- Posterior communicating
Middle cerebral
Identify the artery marked by the arrow labelled 2:
- Anterior cerebral
- Anterior median spinal
- Basilar
- Middle cerebral
- Vertebral
Basilar
The terminal branches of the artery marked by the arrow labelled 2 supply the:
- Auditory cortex
- Motor cortex
- Olfactory cortex
- Sensory cortex
- Visual cortex
Visual cortex
(Terminal branches of the basilar artery supply the posterior cerebral arteries, which in turn supply blood to the occipital lobe of the brain responsible for processing visual information)
Identify the artery marked by the arrow labelled 3:
- Anterior cerebral
- Anterior medial spinal
- Basilar
- Posterior cerebral
- Posterior inferior cerebellar
Anterior medial spinal
The artery marked by the arrow labelled 3 supplies the:
- Pons
- Spinal cord dorsal horn
- Spinal cord lateral horn
- Spinal cord ventral horn
- Trigeminal spinal nucleus
Spinal cord ventral horn
(Anterior medial spinal artery supplies the anterior 2/3 of the spinal cord and runs along the anterior median fissure of the spinal cord, supplying blood to structure in that region. The spinal cord is organised into three main regions: the dorsal, ventral and lateral horns. The dorsal horn receives sensory input, the ventral horn sends motor output and the lateral horn contains autonomic cell bodies.)
Name the artery marked by the arrow labelled 1
- Basilar
- Internal carotid
- Middle cerebral
- Posterior cerebral
- Vertebral
Internal carotid
Through which bone in the skull does the artery labelled 1 pass?
- Ethmoid
- Frontal
- Parietal
- Petrous temporal
- Sphenoid
Petrous temporal
(Passes through the carotid canal, an opening in the petrous temporal bone - 16.2)
Identify the artery marked by the arrow labelled 2
- Anterior cerebral
- Anterior communicating
- Internal carotid
- Middle cerebral
- Posterior cerebral
Anterior cerebral
Vascular lesions of the artery labelled 2 will affect which part of the cortex?
- Auditory cortex
- Frontal and motor cortex
- Insula cortex
- Parietal cortex
- Visual cortex
Frontal and motor cortex
(The ACA supplies blood to the superior and medial portions of the frontal lobe, including the prefrontal cortex, supplementary motor area and primary motor cortex. It also supplies the parietal lobe, including the primary somatosensory cortex.)
What symptoms would you associate with a loss of function of the area supplied by the artery with the arrow labelled 2?
- Behavioural disturbances
- Facial paralysis
- Loss of sensation to the hand
- Loss of taste
- Vocal cord paralysis
Behavioural disturbances
(The symptoms that are most commonly associated with a loss of function of the area supplied by the anterior cerebral artery are: behavioural disturbances, contralateral weakness or paralysis, loss of sensation to the leg and foot, apraxia, gait apraxia, and urinary incontinence)
The region of the cortex marked by the yellow arrow receives its arterial supply from the:
- Anterior cerebral artery
- Anterior spinal artery
- Internal carotid artery
- Middle cerebral artery
- Posterior cerebral artery
Posterior cerebral artery
(Visual cortex)
Which blood vessel supplies the part of the tract marked by the yellow arrow?
- Anterior cerebral artery
- Anterior median spinal artery
- Middle cerebral artery
- Posterior cerebral artery
- Posterior inferior cerebellar artery
Anterior median spinal
(Pyramidal tract)
A
Posterior cerebral artery
B
Basilar artery
C
Anterior inferior cerebellar artery
D
Vertebral artery
Name 2 areas of the brain supplied by A
1 - Occipital lobe
2 - Inferior part of the temporal lobe
(Occipital lobe, inferolateral surface of the temporal lobe, midbrain, thalamus, choroid plexus, cerebral peduncles)
Describe the effects on motor and sensory function of a complete occlusion of the anterior spinal artery at the mid thoracic level.
Loss of motor and sensory function of the lower limb
(Paralysis of the lower limb and trunk, loss of sensation below the level of the lesion, bladder and bowel dysfunction, respiratory compromise)
Identify A
Anterior cerebral artery
Identify B
Internal carotid
State the expected consequence of a lesion resulting from occlusion of vessel A
Loss of motor and sensory function of the lower limb (presents contralaterally)
In the angiogram, identify vessel A name one major
CNS structure that it supplies
Posterior cerebral artery - occipital lobe and inferior temporal lobe
(Occipital lobe, inferior surface of the temporal lobe, midbrain, thalamus, choroid plexus, cerebral peduncles)
In the angiogram, identify vessel B name one major
CNS structure that it supplies
Basilar artery - circle of Willis
In the angiogram, identify vessel C name one major
CNS structure that it supplies
Vertebral artery - brainstem and cerebellum
On the cerebral angiogram identify A
Internal carotid artery
On the cerebral angiogram identify B
Middle cerebral artery
On the cerebral angiogram identify C
Anterior cerebral artery
Through which foramen does A pass to enter the skull?
Carotid canal
Which area of the cortex is supplied by C?
Superior and medial frontal lobe & superior and medial parietal lobe
With reference to the angiogram in which the vertebral artery has been filled, how does the vessel A enter the skull?
Foramen magnum
With reference to the angiogram in which the vertebral artery has been filled, identify vessel B
Basilar artery
With reference to the angiogram in which the vertebral artery has been filled, which blood vessel is indicated by C?
Posterior cerebral artery
With reference to the angiogram in which the vertebral artery has been filled, which brain area is indicated by the letter D?
Occipital lobe
With reference to the angiogram in which the vertebral artery has been filled, give one major role associated with area D
Visual processing
How does vessel A enter the skull?
Carotid canal
Identify vessel B
Anterior cerebral artery
Name one other blood vessel arising directly from vessel A
Middle cerebral artery
Which brain area is supplied by vessel B?
Superior and medial frontal lobe & superior and medial parietal lobe
What functional loss might occur if vessel B became occluded?
Contralateral loss of motor and sensory functions of the lower limb
What is the effect of a blockage to the left anterior cerebral artery?
Contralateral loss of sensory and motor function to (right) leg
What is the effect of a blockage to the right middle cerebral artery?
Contralateral loss of sensory and motor function to (left) arm
What is the effect of a blockage to the left posterior cerebral artery?
Loss of right hemifield vision in both eyes (contralateral homonymous hemianopsia)
(Contralateral homonymous hemianopsia = visual field deficit characterised by loss of vision in the same hall of the visual field of both eyes. The left PCA supplies the left occipital lobe, which receives visual input from the right visual field of both eyes, therefore, damage to the right PCA would result in a loss of visual function in the left hemifield of both eyes.)
What is the effect of a blockage to the anterior spinal artery branches to the medulla?
- Deviation of tongue to side of infarct when protruded
- Contralateral limb weakness
- Vibration sense on contralateral side
(Median medullary syndrome)
What is the effect of a blockage to the hypothalamo-hypophysial portal veins?
Pickardt syndrome - hypothyroidism
The ‘Circle of Willis’ is located in the
Interpeduncular cistern and enclosing the optic chiasm
The anterior cerebral artery travels along the
Longitudinal fissure
The anterior cerebral arterial follows the curvature of
The corpus callosum
Occlusions of the anterior cerebral artery result in
Loss of contralateral lower limb sensation and motor function
The middle cerebral artery enters the
Lateral fissure
The middle cerebral artery supplies the
Lateral aspects of the frontal, temporal and parietal lobes
Occlusions of the middle cerebral artery result in
Loss of contralateral upper limb sensation and motor function
The superior sagittal sinus runs
From anterior to posterior by the inner surface of the frontal and parietal lobes
The superior saggital sinus allows blood to drain from
The lateral aspects of the interior cerebral hemispheres
The superior saggital sinus drains into
Transverse sinus
The superior saggital sinus receives cerebrospinal fluid from
Arachnoid granulations
Rupture of the middle meningeal artery results in
Epidural haemotoma
Rupture of the middle meningeal artery is often caused by
Fracture at the pterion
The vertebral artery enters through the
Foramen magnum
The vertebral artery forms the
Basilar artery
The vertebral artery gives off branches including
Anterior spinal artery and posterior inferior cerebellar artery
(Anterior spinal, posterior spinal, posterior inferior cerebellar, meningeal, medullary, basilar arteries)
The vertebral artery is derived from
Subclavian artery
The vascular structure most commonly involved in extradural haemorrhage
Middle meningeal artery
Which arteries unite to form the basilar artery that then supplies blood to the brain stem?
Vertebral arteries
Occlusion of a middle cerebral arteries is likely to cause
Loss of motor and sensory function in contralateral upper limb
The circle of Willis is
An anastomotic ‘circle’ situated in the interpeduncular cistern and enclosing the optic chiasm
The circle of Willis is composed of which vessels
Anterior cerebral and communicating, internal carotid (middle cerebral branches off), posterior cerebral and communicating (and Basilar)
Vessel 1
Posterior cerebral artery
Vessel 2
Basilar artery
Vessel 3
Vertebral artery
Through what opening does vessel 3 enter the skull?
Foramen magnum
Which region of the brain would be affected by an occlusion of vessel 1?
Occipital lobe
Through which opening does the vessel illustrated enter the skull?
Carotid canal
The artery that supplies the medial frontal cortex
Anterior cerebral artery
The pterion is found at the junction of which four bones?
Sphenoid (greater wing), frontal, parietal and temporal
A skull fracture at the pterion is likely to cause
Epidural haematoma (extradural haemorrhage)
Through which part of the skull does the main vessel illustrated enter?
Foramen magnum
The main artery that supplies the visual cortex bordering the calcarine sulcus?
Posterior cerebral artery
The artery from which the labyrinthine artery to the inner ear branches?
Anterior inferior cerebellar artery
Rupture of a berry aneurysm on the posterior communicating artery will cause
Oculomotor nerve palsy
(Rupture leads to a subarachnoid haemorrhage; compression of the oculomotor nerve causes blown pupils - dilated, nonreactive pupil on the side of the affected nerve, in addition to ptosis, diplopia and difficulty moving the eye up, down or inward)
Superficial cerebral veins from frontal cortex drain into
Superior saggital sinus
The artery supplying the primary visual cortex
Calcarine branch of the posterior cerebellar
1
Anterior cerebral artery
2
Anterior communicating artery
3
Posterior communicating artery
4
Basilar artery
5
Posterior cerebral artery
6
Middle cerebral artery
7
Internal carotid artery
Superior saggital sinus receives
Cerebrospinal fluid and deoxygenated blood from the superior aspects of the brain
Great cerebral vein receives
Deoxygenated blood from the medial cerebrum
Transverse sinus receives
Deoxygenated blood from the superior saggital, occipital and straight sinuses
Transverse sinus drains into
Sigmoid sinus
Sigmoid sinus receives
Deoxygenated blood from the posterior brain and inner ear
Cavernous sinus drains into
Petrosal sinus
Internal jugular vein receives
Deoxygenated blood from the sigmoid sinus and petrosal sinus
Cavernous sinus receives
Deoxygenated blood from the opthalmic veins, facial veins and sphenoparietal sinus
Internal jugular vein exits via
Jugular foramen
3
Carotid pulse point
2
Facial pulse point
1
Temporal pulse point
80% of cerebral flow is delivered by
Internal carotid arteries
20% of cerebral flow is delivered by
Vertebral arteries
The cavernous sinus is the only place where
An artery (ICA) crosses a venous structure
Supplementary blood supply for the anterior spinal artery
Great segmental medullary artery (artery of Adamkiewicz)
