The Skeletal System Functions of Bone Supports and gives shape Protects internal organs Movement Stores calcium Hemopoiesis (blood cell formation)

Long Bones Diaphysis – shaft Medullary cavity – yellow bone marrow (inactive, fatty, found in adults) Epiphyses – ends of bone Epiphyseal line – marks location where two centers of ossification have fused together (If radiograph shows no epiphyseal cartilage then growth has stopped.)

Articular cartilage – cushion that covers epiphyses Endosteum – lines medullary cavity Periosteum – strong membrane covering bone except at joint surfaces Spongy bone – porous bone in the end (may be filled with marrow) Trabeculae – needlelike threads of spongy bone that surround a network of spaces Compact bone – dense, hard

Kinds of Joints Synarthroses – no movement, sutures (cranial bones) Amphiarthroses – slight movement, cartilage connects the articulating bones (pubic bones, vertebrae) Diarthroses – free movement, ligaments and synovial fluid

Diarthroses Ball and socket – shoulder and hip Hinge – elbow and knee Flexion:bending Extension: straightening Pivot – second vertebra in neck Saddle - metacarpal bone of thumb and trapezium (carpal bone) Gliding – successive vertebrae Condyloid – distal end of radius into carpals