Ninja Nerd - Circulatory System | Circle of Willis: Ischemic Strokes

Cerebrovascular Accidents

• Ischemia: decreased oxygen supply to tissues and increased oxygen demand
• Can lead to detrimental effects on the body

Clinical Implications of Vessel Occlusion

Anterior Cerebral Artery

• Supplies primary motor cortex and primary somatosensory cortex
• Occlusion leads to contralateral loss of sensation and motor control in the lower body

Middle Cerebral Artery

• Supplies primary motor cortex and primary somatosensory cortex
• Occlusion leads to contralateral loss of sensation and motor control in the upper body (face and upper limbs)
• Can also lead to Broca's aphasia (inability to produce speech) if Broca's area is damaged

Posterior Cerebral Artery

• Supplies the occipital lobe, which is important for vision
• Occlusion leads to contralateral homonymous hemianopia (loss of visual field)

Basilar Artery

• Occlusion can produce locked-in syndrome, resulting in quadriplegia and preserved vertical eye movements

Anterior Inferior Cerebellar Artery

• Occlusion leads to lateral pontine syndrome
• Can cause facial nerve palsy, vertigo, and hearing loss
• Can also affect the vestibular nuclei, leading to balance and coordination problems

Anterior Spinal Artery

• Occlusion produces medial medullary syndrome
• Can cause hypoglossal nerve palsy, contralateral hemiplegia, and contralateral loss of touch, pressure, and vibration sensations

Posterior Inferior Cerebellar Artery

• Occlusion affects the cerebellum, leading to poor coordination, muscle tone, and balance
• Can also cause vagus nerve palsy, leading to dysphagia and a negative gag reflex
• Can also cause Horner's syndrome (ptosis, miosis, and anhydrosis)

Aneurysms

• Berry aneurysms or saccular aneurysms can occur in the Circle of Willis
• Caused by chronic hypertension or connective tissue disorders
• Can rupture, leading to subarachnoid hemorrhage
• Most common sites:
  • Anterior communicating artery (40%)
  • Middle cerebral artery (34%)
  • Internal carotid artery (20%)
  • Vasila artery (4%)

Cerebrovascular Accidents

• Ischemia results in decreased oxygen supply to tissues and increased oxygen demand, leading to detrimental effects on the body

Clinical Implications of Vessel Occlusion

Anterior Cerebral Artery

• Supplies primary motor cortex and primary somatosensory cortex
• Occlusion leads to contralateral loss of sensation and motor control in the lower body

Middle Cerebral Artery

• Supplies primary motor cortex and primary somatosensory cortex
• Occlusion leads to contralateral loss of sensation and motor control in the upper body (face and upper limbs)
• Damage to Broca's area can cause Broca's aphasia (inability to produce speech)

Posterior Cerebral Artery

• Supplies the occipital lobe, essential for vision
• Occlusion leads to contralateral homonymous hemianopia (loss of visual field)

Basilar Artery

• Occlusion can produce locked-in syndrome, resulting in quadriplegia and preserved vertical eye movements

Anterior Inferior Cerebellar Artery

• Occlusion leads to lateral pontine syndrome
• Can cause facial nerve palsy, vertigo, and hearing loss
• Affects the vestibular nuclei, leading to balance and coordination problems

Anterior Spinal Artery

• Occlusion produces medial medullary syndrome
• Can cause hypoglossal nerve palsy, contralateral hemiplegia, and contralateral loss of touch, pressure, and vibration sensations

Posterior Inferior Cerebellar Artery

• Occlusion affects the cerebellum, leading to poor coordination, muscle tone, and balance
• Can cause vagus nerve palsy, leading to dysphagia and a negative gag reflex
• Can also cause Horner's syndrome (ptosis, miosis, and anhydrosis)

Aneurysms

• Berry aneurysms or saccular aneurysms occur in the Circle of Willis
• Caused by chronic hypertension or connective tissue disorders
• Rupture leads to subarachnoid hemorrhage
• Most common sites:
  • Anterior communicating artery (40%)
  • Middle cerebral artery (34%)
  • Internal carotid artery (20%)
  • Vasilis artery (4%)