What is a Joint? • The area where two or more bones articulate (move). • Joints give structure and flexibility to the skeleton.
Classification Functional Classifications: 1) Synarthroses: Immovable joints 2) Amphiarthroses: Slightly movable joints 3) Diarthroses: Freely Movable
Structural Classifications: 1) Fibrous Joints: Bones are connected by dense fibrous tissue – usu. immovable 2) Cartilaginous Joints: Bones are connected by cartilage (vertebral column, pubic bones) - usu. Slightly movable or immovable 3) Synovial Joints: a joint cavity with fluid allowing highly movable joints.
Synovial Joints • Articular Cartilage covers the ends • Fibrous Articular capsule is formed by the synovial membrane • Joint cavity has lubricating synovial fluid • Reinforcing ligaments usually found.
Types of Synovial Joints: • Plane Joint: Slipping or gliding movement between bones (wrist/ankle) 2) Hinge Joint: Motion on a single plane (elbow) 3) Pivot Joint: Movement of a bone along its longitudinal axis (radius, atlas/axis “no”)
Types of Synovial Joints 4) Condyloid Joint: Oval surfaces (concave/convex) on two bones match (metacarpal/phalange joint-knuckle)
Types of Synovial Joints 5) Saddle Joint: concave/convex surfaces with greater range of movement (carpo-metacarpal joint of your thumb) 6) Ball and Socket Joint: The head of a bone fits into a cuplike socket (femur/acetabulum)
JOINTS GONE BAD • Arthritis: (Arth=Joint itis=Inflammation) *Disease that causes pain, stiffness, and swelling of a joint. *1 out of 7 Americans *Can be caused by bacterial infection or genetic *Synovial membranes thicken, less fluid, more bone friction
Three types of Arthritis • Osteoarthritis (OA): chronic. Cartilage wears out between bones, usu. causes bone spurs • Rheumatoid Arthritis (RA): chronic. An autoimmune disorder where the body destroys its own tissue
3) Gouty Arthritis (Gout): Uric acid accumulates in the blood and is deposited as needle-shaped crystals in the joints. Very painful and can cause joints to fuse. Gout Crystals
Osteoporosis • Loss in bone mass • Leads to thin, brittle bones • A decrease in estrogen can cause it • Poor diet, smoking, and lack of vitamin D also causes