Term | Definition |
Articulations | Joints; the point where 2 bones meet |
Arthrology | Branch of science that studies joint structure, function, and dysfunction |
Synarthroses | Fibrous joints; collagen fibers from one bone penetrate the adjacent bone, anchoring the bones in place; suture joints |
Amphiarthroses | Cartilaginous joints; two bones are joined by cartilage making it slightly movable; symphysis pubis, vertebrae |
Diarthroses | Synovial joints; freely movable; most numerous and versatile |
Joint capsule | Sheet of connective tissue that encloses the joint cavity, extending from the periosteum of each of the articulating bones |
Synovial membrane | Moist, slippery membrane that lines the inside of the joint capsule, where it secretes synovial fluid |
Joint cavity | Small space between the bones that allows for freedom of movement; contains synovial fluid |
Synovial fluid | Slippery, viscous fluid that has the consistency of an egg white; lubricates the joint, nourishes the cartilage, and contains phagocytes to remove debris |
Articular cartilage | Thin layer of hyaline cartilage that covers the bone surfaces; permits friction-free movement |
Ligaments | Tough cords of connective tissue that help bind the bones more firmly together |
Bursa | Small sacs of synovial fluid; facilitate movement and ease friction, residing in areas where muscles and tendons pass over bony prominences |
Humeroscapular joint | Shoulder; articulation of the humerus and the scapula |
Temporomandibular joint | Jaw; articulation of the mandible and the temporal bone |
Sacroiliac joint | The point where the sacrum and the ilium meet |
Pivot joint | A projection from one bone articulates with a ring-shaped socket of another bone, allowing the bones to rotate, or pivot; the dens of the axis articulating with the atlas, the radioulnar joint |
Hinge joint | Allow only back and forth movement; the convex surface of one bone fits into a concave depression on another; the elbow, the knee, interphalangeal joints |
Gliding joint | 2 relatively flat bone surfaces slide over each other; least mobile of all the synovial joints; tarsals, carpals, and articular processes of the vertebrae |
Ball-and-socket joint | Ball shaped head of one bone fits into a cup-like socket of another bone; widest range of motion; shoulder and hip |
Saddle joint | Concave in one direction, convex in the other; allows for back and forth and side to side movement , although the side to side movement is limited; only in the thumbs |
Condyloid joint | Oval convex surface on one bone fits into a similarly shaped depression on another; allow flexion and extension as well as side to side movements; the articulation of the radius and carpals and the joints at the base of the fingers |
Flexion | Bending a joint so as to decrease the angle of the joint |
Extension | Straightening a joint, increasing the angle between the bones |
Hyperextension | Extreme extension of a joint beyond its normally straight position |
Dorsiflexion | Moving the toes upwards |
Plantar flexion | Moving the toes downward |
Abduction | Movement of a body part away from the midline of the body |
Adduction | Movement of a body part toward the midline of the body |
Circumduction | Distal end of an appendage moves in a circle |
Supination | Movement that turns the palm upward |
Pronation | Movement that turns the palm downward |
Internal rotation | When a bone spins toward the body's midline |
External rotation | When a bone spins away from the body's midline |
Inversion | Foot movement that turns the sole medially, toward the other foot |
Eversion | Foot movement that turns the sole laterally, away from the other foot |
Protraction | Moves a part forward |
Retraction | Moves a part backward |
Glenohumeral joint | Shoulder, humeroscapular joint |
Humeroulnar joint | Articulation of the humerus and the ulna; elbow |
Humeroradial joint | Articulation between the humerus and the head of the radius; elbow |
Tibiofemural joint | Largest joint in the body and the most complex; knee |
Fibular collateral ligament | Ligament on the fibula (lateral) side of the knee that keeps the knee from rotating when extended |
Tibial collateral ligament | Ligament on the tibia (medial) side of the knee that keeps the knee from rotating when extended |
Posterior cruciate ligament | PCL; stabilizes the knee and limits sideways movement |
Anterior cruciate ligament | ACL; stabilizes the knee and keeps it from hyperextending |
Lateral meniscus | Slightly concave piece of cartilage on the lateral side that cradles the condyles and absorbes shock |
Medial meniscus | Slightly concave piece of cartilage on the medial side that cradles the condyles and absorbs shock |
Arthroplasty | Surgical procedure that replaces a diseased joint with a prosthesis |
Prosthesis | Artificial device |
Arthritis | Inflammation of a joint |
Osteoarthritis | "Wear-and-tear" arthritis; common effect of aging; effects the hips knees, intervertebral joints, and fingers |
Rheumatoid arthritis | Autoimmune disease; degeneration of the articular cartilage and thickening of the synovial membrane; causes pain and joint deformity; no cure; drug and physical therapy can help control symptoms |