Immune system attacks joint tissue from allergy, infection, genetics Exercise, physical therapy, antiinflammatories, surgery to realign or replace. When squeezed, fluid comes out to fill spaces between surfaces Relax and fluid goes back into cartilage Distribution of nutrients and waste. Aka articular disc Subdivide cavity Channel fluid flow Allow variation in articular shapes. Extracapsular ligaments interconnect bones Support wall of joint Intracapsular ligaments prevent extreme movement and damage. Tendons attach muscle to bone Not part of joint, but run around and across joint.
Diarthrosis has movement, but less strength.
Movement beyond normal range can damage mobile joint. Need to stabilize joint to limit range of motion and reduce risk of injury. When muscle pulls on bone, is movement encouraged or opposed. Heavy capsule with intra and extracapsular ligaments Tendons and massive muscles. Elbow has interlocking articulating bones, with capsule, and ligament support Shoulder joint has only ligaments, muscles and tendons.