Anatomy Physiology The Skeletal System Part 4 JOINTS

Anatomy & Physiology The Skeletal System- Part 4 JOINTS

JOINTS � aka Articulations � 2 Functions: Hold Bones Together 2. Allows otherwise rigid skeleton to have some flexibility 1.

Classification of Joints � Functionally � Structurally � Named according to how much movement allowed @ joint to presence of fibrous tissue, cartilage, or a joint cavity separate the articulated bones

Functional Joints � Synarthrosis � Immovable joints � Skull bones � Amphiarthrosis � Slightly movable joints � Symphysis pubis � Diarthrosis � Freely movable joints � Ball & Socket or Hinge Joints

Structural Joints 1. Fibrous Joints � Bones united by fibrous tissue � Joint connecting distal tibia & fibula 2. Cartilaginous Joints � Bone ends connected by cartilage � Pubic symphysis 3. Synovial Joints � Articulating ends of bone separated by joint cavity

4 Features of Synovial Joints 1. Articular Cartilage � Hyaline cartilage covers ends of bones 2. Fibrous Articular Capsule � Joint surfaces enclosed by capsule of fibrous CT � Capsule lined by synovial membrane 3. Joint Cavity � Contains synovial fluid 4. Reinforcing Ligaments � Reinforce fibrous articular capsule

Types of Synovial Joints 1. PLANE JOINT � Articular surfaces flat � Allow gliding movement (w/out rotation) � Example: intercarpal joints of wrist & ankle

Types of Synovial Joints 2. HINGE JOINT � cylindrical end of bone fits into troughshaped surface of another bone � Angular movement allowed in 1 plane � Examples: elbow, knee, interphalangeal joints

Types of Synovial Joints 3. PIVOT JOINT � Rounded end of 1 bone fits into sleeve or ring of another bone � allows 1 bone to rotate along its long axis � Example: joint between atlas & dens of axis

Types of Synovial Joints 4. CONDYLOID JOINT � “knuckle-like” � Egg-shaped end of 1 bone fits into oval concavity in another bone � Allows for moving bone to travel side-to-side & back-and-forth but cannot rotate along its long axis � Example: metacarpophalangeal joint

4. CONDYLOID JOINT

Types of Synovial Joints 5. SADDLE JOINTS � Each articular surface has convex & concave areas � Same movements as condyloid joints � Example: twiddling your thumbs

Types of Synovial Joints 6. BALL & SOCKET JOINTS � Spherical head of 1 bone fits into a round socket formed by 1 or more bones � Allows movement is 3 dimensions(most freely moving of synovial joints)

SPRAINS � Ligaments or tendons reinforcing a joint are damaged by excessive stretching or tearing � Both have poor blood supply so heal slowly

ARTHRITIS � “inflammation of a joint” � General term for >100 different diseases � Most wide-spread, disabling disease in USA � Onset: same symptoms: joint stiffness & swelling � Synovial membrane inflammed thickens less synovial fluid increased friction

Rheumatoid Arthritis � Autoimmune disorder � Adult onset or Juvenile onset � Women 3 x more often than men � Any synovial joint could be affected, often symmetrical involvement � disfiguring

Rheumatoid Arthritis

Osteoarthritis � Most common form of arthritis � Chronic degenerative condition: “wear-and- tear” � Affects articular cartilage (eventually breaks down) increased friction bone spurs develop restricts movement

Osteoarthritis