Lecture Notes: Blood Supply to the Spinal Cord

Presented by Peter from Anatomy Zone

Overview

• Focus on arterial supply and venous drainage of the spinal cord.

Arterial Supply

Two Main Sources:

1. Vertical Vessels

   • Origin: Medulla oblongata inside the cranial cavity.
   • Branches: Descend vertically along the spinal cord.
   • Key Vessels:
     • Anterior Spinal Artery:
       • Formed by anastomosis of vertebral arteries.
       • Runs down the spinal cord along the ventral median fissure.
     • Posterior Spinal Arteries:
       • Two arteries originating from vertebral arteries.
       • Run down the posterolateral aspect of the spinal cord.

2. Segmental Spinal Arteries

   • Supply: Feed into the spinal cord at each vertebral segment.
   • Entry: Intervertebral foramina along with spinal nerve roots.
   • Region-Specific Origins:
     • Cervical: Vertebral and deep cervical arteries.
     • Thoracic: Posterior intercostal arteries.
     • Abdomen: Lumbar arteries.
   • Branches:
     • Posterior Radicular Artery: Follows dorsal nerve roots.
     • Anterior Radicular Artery: Follows ventral nerve roots.
     • Segmental Medullary Artery:
       • Reinforces vertical arteries.
       • Not present at every level.
       • Arterial Radicularis Magna: Largest, located in lower thoracic and upper lumbar regions.

Venous Drainage

• Longitudinal Veins: Anterolateral and posterolateral veins running along the spinal cord.
• Anterior and Posterior Spinal Veins: Additional longitudinal veins.
• Drainage Pathway:
  • Radicular Veins: Drain into the internal vertebral venous plexus located in the extradural space.
  • Internal Vertebral Venous Plexus: Drains into the external vertebral venous plexus.
  • Systemic Veins: Blood returns via ascending lumbar vein, azygos vein, and hemiazygos vein.

Additional Notes

• Understanding the reinforcement role of segmental medullary arteries is crucial for comprehension of spinal blood supply.
• The venous drainage mirrors the arterial supply in terms of orientation and names.