Bone marrow edema occurs accumulation of excessive fluid inside the bone marrow. Bone injuries may cause fluids to accumulate due to a protective mechanism in the body. Bone Marrow Edema may also occur from underlying diseases such as osteoporosis or tumors. 

Bone marrow consists of spongy, flexible structures inside the bones and generates new blood cells such as RBC, WBC, and platelets. The blood cells transport oxygen, fight infection and clot the blood to help prevent excessive bleeding from an injury.