Blood supply content

Question 1

what forms the circle of willis

Answer 1

o Anterior cerebral artery
o Middle cerebral artery
o Posterior cerebral artery

Question 2

what supplies the pons

Answer 2

basilar artery

Question 3

what arteries bring blood to the brain

Answer 3

vertebral and internal carotid artery

Question 4

ACA

Answer 4

→ Supplies the medial cortical surfaces of the frontal and parietal lobes.
o Lower limb – paralysis of the contralateral lower limb, sensory loss of contralateral lower limb, mental impairments (easily distracted, indecisiveness), urinary incontinence.
o Prefrontal cortex

Question 5

MCA

Answer 5

→ Supplies entire lateral cortical surfaces of the frontal, partietal and temporal lobes.
o Head, upper limb and thoracic areas.
o Hearing and language areas (Wernicke’s area, Broca’s area and angular gyrus)
o Frontal cortex
o Basal ganglia
o Internal capsule (posterior)
→ Signs of involvement – paralysis of contralateral upper limb, head and trunk, contralateral sensory loss of upper limb, head and trunk, aphasia (if dominant hemisphere), cognitive impairments.

Question 6

PCA

Answer 6

→ Supplies occipital lobe and inferior cortical surfaces of the temporal lobe and parietal lobe.
o Terminal branches anastomose with branches of the MCA (watershed area) on inferior margin of these lobes.
o Mainly visual areas and subthalamic nuclei.
→ Signs of involvement – contralateral homonymous hemianopia – injury to one side of the brain will affect the contralateral visual field in each eye.

Question 7

vertebral basilar artery system

Answer 7

→ Basilar and vertebral arteries give rise to many small branches that supply the brainstem, cerebellum and spinal cord.
→ Branches – posterior inferior cerebellar artery (PICA), anterior superior cerebellar artery (AICA) and superior cerebellar artery (SCA).

Question 8

blood supply to the cerebellum

Answer 8

→ Basilar artery bifurcates to become left and right superior cerebellar arteries (SCA) and left and right anterior inferior cerebellar arteries (AICA).
→ SCA’s – supply superior cerebellum and part of dorsal pons.
→ AICAs – supply central core and ventral areas of the cerebellum.
→ Smaller pontine arteries (arise from basilar artery) supply ventral pons.

pathway for remaining segments of cerebellum and brainstem:
o 2 additional arteries complete the blood supply – left and right inferior posterior cerebellar arteries (PICA) and anterior spinal artery (ASA).
o PICA – supply inferior areas of the cerebellum and small regions of the lateral medulla.
o ASA – supplies blood to the medulla.

Question 9

blood supply to the spinal cord

Answer 9

Blood supply of the spinal cord
→ 2 spinal arteries run vertically along the cord:
o Anterior spinal artery (1 x) from vertebral artery.
o Posterior spinal artery (2x) from posterior inferior cerebellar artery (PICA).

Question 10

venous system

Answer 10

→ Cerebral venous drain into dural venous sinuses.
→ 5 main and interconnected sinuses that manage majority of venous return.
→ Superior and inferior sagittal sinuses and straight sinus converge at the confluence.
→ From the confluence, the transverse sinus continues bi-laterally and curves into the sigmoid sinus to meet the opening of the internal jugular vein.
→ These drain into the internal jugular vein (left and right) returning blood to the cardiopulmonary system.