Blood supply of the brain & spinal cord

Read written notes.

Images on blood vessels supplying the brain:

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Blood supply to the spinal cord:

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Clinical Anatomy

BRAIN

• Too delicate to bear hypoglycaemia/anoxia/hypoxia
• Damage
  • Reversible beyond 3 minutes
  • Irreversible beyond 7 minutes
• Arteries are ‘end arteries’
• Conditions that may arise:
  • Aneurysms
  • Stroke (haemorrhage, thrombosis, embolism)
  • Medial medullary (Dejerine) syndrome
    • Ant spinal artery
  • Lateral medullary (Wallenberg) syndrome
    • Post spinal artery

Anterior cerebral artery

• Supplies the paracentral lobule (medial aspects of the precentral & postcentral gyri)
• Occlusion
  • cause restricted contralateral motor & somatosensory deficits
    • primary lower limbs and perineum

Middle cerebral artery

• Supplies most of the precentral & postcentral gyri
• Occlusion
  • cause major motor & somatosensory deficits
  • If left hemisphere affected
    • speech/language deficits are almost invariably found

Posterior cerebral artery

• Supplies primary visual cortex in the occipital lobe
• Occlusion
  • visual field losses
  • may cause other deficits referable to the midbrain and diencephalon

SPINAL CORD

• Ischaemia
  • segmental reinforcement lost during fractures/dislocations
  • Lead to
    • muscle weakness/paralysis
• Obstructive arterial disease
• Paraplegia
  • obstruction of anterior spinal artery
• Hypotension
  • drop of BP for 3-6 minutes
  • Cause
    • loss of sensation & movement of affected segment
• Vertebral venous plexus
  • alternate pathway if SVC/IVC obstructed
  • route for metastases from pelvis to brain