Skeletal System Glossary

Abduction The movement away from the body’s midline.
Adduction Movement towards the body’s midline.
Anatomy The study of body structures and their relation to other structures in the body.
Artery A blood vessel that carries blood away from the heart.
Articulation Sometimes called a joint, where bones meet.
Ball‐and‐socket joint A synovial joint in which the rounded surface of one bone fits within the cup‐shaped depression of the socket of the other bone.
Calcification Deposition of mineral salts in a framework formed by collagen fibers in which tissue hardens.
Cancellous A type of structure as seen in spongy bone tissue; resembles a latticework structure.
Cartilage Strong, tough material on the bone ends that helps to distribute the load within the joint; the slippery surface allows smooth movement between the bones; a type of connective tissue.
Cartilaginous joints A joint where the bones are held together tightly by cartilage; little movement occurs in this joint. This joint does not have a synovial cavity.
Collagen A protein that makes up most of the connective tissue.
Condyloid joint A synovial joint that allows one oval‐shaped bone to fit into an elliptical cavity of another.
Diaphysis The shaft of a long bone.
Epiphysis The end of the long bone.
Fibrous joint A type of joint that allows little or no movement.
Flexion Movement where there is a decrease in the angle between two bones.
Fracture A break in a bone.
Gliding joint A synovial joint whose articulating surfaces are usually flat, allowing only side‐to‐side or back‐and‐forth movement.
Haemopoiesis The formation and development of blood cells in the bone marrow after birth.
Histology The microscopic study of tissue.
Homeostasis A state whereby the body’s internal environment remains relatively constant within physiological limits.
Hormone The secretion of endocrine cells that have the ability to alter the physiological activity of target cells in the body.
Insulin-like growth factor (IGF)  Produced by the liver and other tissues, this is a small protein that's produced in response to hGH.
In utero Within the uterus.
Kinesiology The study of the movement of the body.
Lacuna A small, hollow space found in the bones where osteocytes lie.
Lamellae Rings of hard, calcified matrix found in compact bones.
Ligaments Tough fibrous bands of connective tissue that hold two bones together in a joint.
Macrophage Cells that engulf and then digest cellular debris and pathogens.
Marrow A sponge‐like material found in the cavities of some bones.
Mesenchyme Embryonic connective tissue from which nearly all other connective tissue arises.
Metaphysis The aspect of a long bone that lies between the diaphysis and the epiphysis.
Ossification The formation of bone; sometimes called osteogenesis.
Osseous Bony.
Ossicle A small bone of the middle ear – the malleus, the incus, the stapes.
Osteoblasts Cells that arise from osteogenic cells; these cells participate in bone formation.
Osteoclasts Large cells that are associated with absorption and removal of bone.
Osteocytes Mature bone cells.
Osteon The basic unit of structure in adult compact bone.
Osteophytes Overgrowth of new bone around the side of osteoarthritic joints; also known as spur growth.
Periosteum Membrane covering bone consisting of osteogenic cells, connective tissue, and osteoblasts. This is vital for bone growth, repair, and nutrition.
Pivot joint A joint where a rounded or conical‐shaped surface of a bone articulates with a ringformed partly by another bone or ligament.
Remodeling Replacement of old bone by new.
Resorption Absorption of what has been excreted.
Saddle joint A synovial joint articulates the surface of a saddle‐shaped bone on the other bonethat is said to be shaped like the legs of the rider.
Spongy (cancellous) bone tissue Bone tissue comprised of an irregular latticework of thin platesof bone known as trabeculae. Some bones are filled with red bone marrow, and these are found inshort, flat and irregular bones as well as the epiphyses of long bones.
Synovial cavity The space between the articulating bones of a synovial cavity, filled with synovial fluid.
Synovial fluid A clear pale, yellow, viscid fluid. It lubricates joints.
Trabeculae A network of irregular latticework of thin plates of spongy bones.