The skeleton

1. The skeleton Bones and joints

2. Classification of joints • Function • Immoveable = synarthroses [sutures of skull] • Slightly moveable = amphiarthroses [intervertebral discs; pubic sympysis] • Freely moveable = diarthroses [synovial joints – knee, elbow

3. Synovial joints – most common joint in body (pg 102) • Saddle – waving hand • Ball-and-Socket – arm/leg circles • Pivot – rotation – proximal ends radius & ulna; atlas & axis • Hinge –up & down – elbow, knee • Gliding – sliding/twisting various planes – wrist, ankle • Condyloid - shallow ball & socket – between metacarpals & phalanges

4. Sprains • Stretched or torn ligaments • Accompanied by internal bleeding (bruising), swelling and pain • Ankle most common • Take a long time to heal because ligaments have few cells and poor blood supply • Stretches mend with time • Tears may require surgery to remove damaged tissue and stabilize with a piece of tendon or repositioning other ligaments

6. Bursae • Bursa – a flattened fibrous sac lined with synovial membrane and containing a thin film of synovial fluid • Found where ligaments and bones rub together • These bags of fluid act as ball bearings to reduce friction during joint movements

8. Arthritis • General term for joint inflammation • Most common – osteoarthritis – degenerative wear and tear – 20 million Americans >45 • Bony spurs form as cartilage wears away and bones thicken • Increased friction causes painful inflammation • OTC meds can help, surgical joint replacement in severe cases; injections of hyaluric acid (a component of hyaline cartilage) can reduce knee pain temporarily

10. Rheumatoid arthritis • Also causes joint inflammation but it is caused by the body’s own immune system (autoimmune disorder) which mistakenly attacks the joint tissues