What is the blood supply to the bone and how do drugs given via the IO route pass into the circulation?

  • Drugs are delivered into the marrow cavity in cancellous bone:
    • A highly vascular compartment filled with a network of venous sinusoids
    • Non-collapsible even in shocked states
  • Connect to a series of longitudinal ‘Haversian’ canals in cortical bone
    • Contain a tiny artery and vein
  • Cross-connect by a series of transverse ‘Volkmann’ canals:
    • Penetrate through the hard cortex of the bone
    • Connect to larger periosteal veins and onto the central circulation