Joints A joint, or articulation, is the place where two bones come together.  Fibrous- Immovable; connect bones, no movement. (skull and pelvis).  Cartilaginous- slightly movable; bones are attached by cartilage, a little movement (spine or ribs).  Synovial- freely movable; much more movement than cartilaginous joints. Cavities between bones are filled with synovial fluid. This fluid helps lubricate and protect the bones.

The Synovial Joint Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 5.28

4 COMPOSITION OF JOINTS Ligament - connects bone to bone Tendon - connects muscle to bone Bursa - fluid filled sac that allows bones to move easily over others Cartilage – connective tissue that cushions the joint at end of bones and between bones

Types of Synovial Joints Based on Shape Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Hinge Joint A hinge joint allows extension and retraction of an appendage. They are found in the elbow and knee.

A ball and socket joint allows for radial movement in almost any direction. They are found in the hips and shoulders Ball and Socket Joint

In a gliding or plane joint bones slide past each other. Mid-carpal and mid-tarsal joints are gliding joints. (Hands, Feet) Gliding Joint

This type of joint allows rotary movement. The joint between the atlas and the axis in the neck and the joint in the forearm are pivot joints. Pivot Joint

Common Disorders of the Skeletal System

Osteoporosis  porous bone that breaks easily and are weaker  loss of minerals, especially calcium  Common in spine, hips and wrists

Arthritis Osteoarthritis- cartilage wears away ○ Usually affects weight bearing joints (knees, hips, vertebrae and fingers) ○ Wear and tear over time Rheumatoid arthritis- synovial membrane inflames ○ Autoimmune disease ○ Can occur at any age  inflammation of the joints

Bursitis  inflammation of the bursa (fluid filled sac surrounding the joint)  A bursa can become inflamed from injury, infection, or due to an underlying rheumatic condition  localized pain or swelling, tenderness, and pain with motion of the tissues in the affected area.

Tendonitis  inflammation of the tendon  Causes: Sudden increase in use Overuse or repetitive movement Underlying biomechanical issue

Sprains and Strains  Sprain stretched or torn ligament fall, twist or hit can move a joint out of place mild to severe  Strain stretched or torn muscle or tendon may occur suddenly or over time