Types of bone marrow Gelatinous tissue found in the inner spaces of bone that contains progenitor cells and stromal cells Types of bone marrow red marrow hematopoietic tissue composition 40% water 40% fat 20% protein yellow marrow fatty tissue composition 15% water 80% fat 5% protein Function primary function of hematopoiesis controls the inner diameter of bone Red Bone Marrow Location most commonly found in flat bones ribs, ilium, sternum, vertebrae, skull epiphysis/metaphysis of long bone (children only) Function contains mesenchymal stem cells and hematopoietic stem cells red marrow slowly changes to yellow marrow with age Yellow Bone Marrow Location most commonly found in diaphysis or shaft of long bones femur, humerus, tibia Function contains mostly fat cells may revert to red bone marrow if there is an increased demand for red blood cells (e.g. trauma) Bone Marrow Examination Biopsy location anterior or posterior iliac crest sternum tibia indications malignancies (most common) multiple myeloma, lymphoma, leukemia, metastatic disease infection TB (rare) technique needle/trochar biopsy open surgical biopsy Clinical Aspects of Cell Therapy Bone Marrow Aspirate applications in orthopedic surgery fracture union/non-union osteonecrosis mesenchymal tissue engineering (e.g., bone, ligaments, cartilage)