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Bone Marrow

Bone marrow is soft tissue found mainly inside the long bones, vertebrae, and pelvic bones of the body. It is made up of red marrow, which produces red and white blood cells and platelets, and yellow marrow, which contains fat and connective tissue.

People are born with only red bone marrow. As a person matures, the red marrow in many of the bones is replaced by yellow marrow. By adulthood, only about half of the bone marrow is red. Red bone marrow is found mostly in the ribs, breastbone, shoulder blades, collarbones, hip bones, skull, and spine.

By Healthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer Brian Leber, MDCM, FRCPC - Hematology
Current as of November 19, 2012

WebMD Medical Reference from Healthwise

Last Updated: November 19, 2012
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.