By printing and/or reading this article, you agree that you accept all terms and conditions of use, as specified online. Skeletal System Your bones perform a number of essential functions. They support and protect your internal organs. They act as levers and braces for your muscles to help you move. They also produce and store blood cells in the bone marrow. Although we may think of bones as being static, bones are actually living, growing tissue. Throughout a person's lifetime, old bone is removed (resorption) and new bone is added to the skeleton (formation). Normally, during childhood and the teenage years, new bone is added faster than old bone is removed. According to the National Institutes of Health, three types of tissue can combine to make up mature bones: Compact tissue - This is the hard outer portion of most bones Cancellous tissue -This is the spongy tissue inside the bones that contains bone marrow, which makes blood cells Subchondral tissue - This is the smooth bone tissue of the joints A layer of cartilage covers subchondral tissue to cushion the movement of joints. You can follow the links below to learn more about conditions and diseases of the bones. Avascular necrosis: see Osteonecrosis Bone cancer: see Bone Cancer Bone cyst, unicameral: see Bone Tumors - Benign Bone fractures: see Bone Fractures Bone loss, kidney disease: see Bone Loss & Kidney Disease Bone loss, osteoporosis: see Osteoporosis Bone tumors, cancerous: see Bone Cancer Bone tumors, non-cancerous: see Bone Tumors - Benign Calcium, osteoporosis: see Calcium and Osteoporosis Cancer, bone: see Bone Cancer Chondrosarcoma: see Bone Cancer Clubfoot: see Clubfoot Craniofacial Disorders: see Craniofacial Disorders Curvature of the spine: see Curvature of the Spine DEXA scan: see DEXA Scan Ewing's sarcoma: see Bone Cancer Fibrous dysplasia: see Bone Tumors - Benign Fractures: see Bone Fractures Giant cell tumor: see Bone Tumors - Benign Hip fracture: see Hip Fracture Hypercalcemia: see Hypercalcemia Hyperparathyroidism: see Parathyroid Glands Ischemic necrosis: see Osteonecrosis Joint replacement: see Joint Replacement Kidney disease, bone loss: see Bone Loss & Kidney Disease Kyphosis: see Curvature of the Spine Leukemia: see Leukemia Multiple myeloma: see Multiple Myeloma and Plasmacytoma Orthopedics: see Orthopedics Osgood-Schlatter disease: see The Knee Osteoarthritis: see Osteoarthritis Osteochondritis dissecans, knee: see The Knee Osteochondroma: see Bone Tumors - Benign Osteodystrophy, renal: see Bone Loss and Kidney Disease Osteoid osteomas: see Bone Tumors - Benign Osteomalacia: see Osteomalacia and Rickets Osteonecrosis: see Osteonecrosis Osteopenia: see Osteoporosis Osteopetrosis: see Osteopetrosis Osteoporosis: see Osteoporosis Osteosarcoma: see Bone Cancer Paget's disease of bone: see Paget's Disease of Bone Physical therapy: see Rehabilitation Plasmacytoma: see Multiple Myeloma and Plasmacytoma Rickets: see Osteomalacia and Rickets Scheuermann's Disease: see Curvature of the Spine Scoliosis: see Curvature of the Spine Spondylolysis, spondylolisthesis: see The Spine Stress fractures: see Bone Fractures Tumors, non-cancerous: see Bone Tumors - Benign Ultrasound: see Ultrasound Unicameral bone cyst: see Bone Tumors - Benign All Concept Communications material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns. © Concept Communications Media Group LLC Online health topics reviewed/modified in 2008 | Terms of Use/Privacy Policy By printing and/or reading this article, you agree that you accept all terms and conditions of use, as specified online. Copyright © St. Joseph Healthcare | Privacy Statement