The two main types of arthritis are:

Osteoarthritis. Osteoarthritis occurs when the smooth cartilage that lines and protects the bone gets damaged and erodes, causing the joint space to continually become narrower. Degeneration of joint cartilage is the most common cause of osteoarthritis; however, prior injury or damage to the joint from trauma or infection are also causes.

Bone spurs (small, irregular bony outgrowths from the edges of a joint surface), joint stiffness, swelling and limited range of motion are all symptoms of osteoarthritis.

Rheumatoid Arthritis. Rheumatoid Arthritis occurs when the joint lining becomes inflamed and secretes more fluid than usual causing the joint to become swollen.  The cartilage then becomes rough and pitted.  If left untreated, bone erosions, tendon inflammations and tendon ruptures can occur. 

Symptoms of RA include fatigue, loss of appetite, low fever, pain, stiffness or swelling in the joints, limited range of motion, morning stiffness in a joint lasting more than one hour, deformities of the hands and feet, round and painless nodules under the skin, skin redness or inflammation, swollen glands, burning, itching or discharge in the eyes, and numbness or tingling.