Understanding Medullary and Marrow Cavity

Sep 15, 2024

Medullary Cavity (Marrow Cavity) Lecture Notes

Terminology

  • Medullary Cavity: Also known as the Marrow Cavity.
    • Important for lab exams to label it as "medullary cavity."

Structure and Contents

  • Location: Located in the diaphysis of long bones.
  • Contents:
    • Contains fat or bone marrow and blood vessels.

Types of Marrow

  1. Red Marrow
    • Function: Hematopoiesis (blood cell production).
    • Population: Mainly found in infants or fetuses.
  2. Yellow Marrow
    • Function: Stores triglycerides or fats.
    • Population: Found after birth and in adults.
    • Conversion: Can convert to red marrow if more blood cells are needed, and reverts back once the crisis is resolved.

Function of Medullary Cavity

  • Weight Reduction: Minimizes the weight of the bone by reducing dense bony material where not needed.
  • Engineering: Provides maximum strength with minimum weight.

Clinical Relevance

  • Fatty Marrow and Fractures
    • Fatty Emboli: Fat from the medullary cavity may enter blood vessels after a bone fracture.
    • Impact: Fat can travel to the lungs and lodge there, causing issues.
    • Associated Condition: Known as a fatty embolism, similar to pulmonary embolisms, which can be caused by blood clots, air, or even a catheter.

Clinical Note

  • It's essential to understand the risk of fatty emboli when dealing with fractures of long bones, as it is a significant clinical condition to be aware of.