Plates include both oceanic crust and continental crust. Stable subduction zones involve the oceanic lithosphere of one plate sliding beneath the continental or oceanic lithosphere of another plate due to the higher density of the oceanic lithosphere. That is, the subducted lithosphere is always oceanic while the overriding lithosphere may or may not be oceanic.
The exact cause of arthritis is unknown. However, there are a number of risk factors associated with various arthritic conditions. A risk factor increases the chances that a person will develop a disease or condition.Risk factors for osteoarthritis (OA) include heredity and the wear and tear of aging.he exact cause of arthritis is unknown. However, there are a number of risk factors associated with various arthritic conditions. A risk factor increases the chances that a person will develop a disease or condition.
Introduction. Rheumatoid arthritis (RA) is an autoimmune disease where the body's immune system mistakenly attacks the synovium, a thin membrane that lines the joints. It causes chronic inflammation that leads to pain, swelling, and stiffness.Eventually, bones and joints can be damaged, leading to disability.ymptoms of RA include: 1  Morning stiffness -- waking up with stiff joints, often the wrists and base of the fingers, ankles, balls of the feet, elbows, or knees. 2  Joint pain with warmth, swelling, tenderness, and stiffness of the joint after resting. 3  Limited range of motion in the affected joints. 4  Fatigue.