'Arthritis' comes from the Greek words meaning 'inflammation of the joint.' There are more than 100 kinds, the most common being rheumatoid osteoarthritis.

Back pain is frequently caused by a musculoskeletal (musk-you-low-SKEL-ih-tal) spasm after heavy lifting, prolonged stooping activities, or even minor trauma.

A spinal 'disk' is the rubbery, hockey puck-shaped structure of the spine that separates the vertebrae from each other, adding flexibility to the spine.

Pain in the area of the face may be caused by a variety of sources: a toothache, a sinus infection, an eye infection, a sunburn, or other problems. Eye pain may be the result of eyestrain, an improper eye wear prescription, infection, or glaucoma, a disorder in which fluid in the eye is blocked.

About half of all Americans adults have muscle pain, ranging from mild to chronic. The pain can be caused by a variety of factors, such as strain, overuse, trauma, accidents, and even emotional stresses.

Neck pain can be caused by a number of things, ranging from tension headaches to physical injury to dental problems. If your neck is hurting, it's important to identify the source of the pain.

'Neuralgia' (noo-RAL-juh) is pain that's caused by damage to nerves. Symptoms typically include sharp, searing pain in the face lasting 10 seconds or less, which may occur many times throughout the day.

When arteries that supply the heart with blood become progressively clogged over time with cholesterol and other deposits, they can cut off the heart's supply of oxygen and cause chest pain called angina (an-JYE-nuh).

Pain in the pelvic area can be caused by a variety of factors. It may be sciatica (sigh-A-tih-kuh), a pain or discomfort that travels down the buttock and leg in the path of the sciatic (sigh-A-tick) nerve, the body's largest nerve.

Phantom pain is felt in an amputated or paralyzed limb. It's a well-known medical phenomenon--not a psychiatric disturbance. The patient can still feel the pain of the missing limb, which is common after amputation while the nerve endings are learning to adjust to their new condition.

'Reflex sympathetic dystrophy' is a controversial condition whose symptoms include prolonged pain following an injury, trauma, surgery, infection, or heart disease that's usually more severe than the injury itself.

The sacrum (SACK-rum) is the wedge-shaped bone created by the fusion of five vertebrae at the back of the pelvis, above the tail bone, which supports the lumbar vertebrae.

Sciatica (sye-AT-tick-kuh) pain extends along the path of the sciatic nerve and its branches, which run over the buttocks and down the outside of the leg to the toes.

Shingles is a disease of the skin and nerves caused by a virus called 'herpes zoster' (ZAHS-tur), the same virus that causes chicken pox. Shingles is an acute inflammation of the tissues of the spinal and cranial nerves.

Spinal disks are the fibrous pads between the vertebrae containing soft, gel-like centers that provide cushioning and flexibility. These disks are the spine's shock absorbers.

Spinal stenosis (stuh-NO-sis) is an abnormal narrowing of the spinal canal, resulting in damaging pressure on the spinal nerves. It occurs primarily in middle-aged or elderly people and is caused by osteoarthritis or an injury.

Thoracic (tho-RA-sick) outlet syndrome refers to a group of symptoms caused by the compression or irritation of the nerves and blood vessels in the thoracic area between the neck and abdomen, where the heart and lungs are.

'T-M-J' stands for 'Temporomandibular (TEM-per-oh-man-DIB-you-lur) Joints, which are the two joints that connect your jaw to your skull. When these joints are out of place, they can cause many problems, such as clicking or popping of the jaw joints, pain in or around the joint, and a locking-up, or limited opening, of your mouth.

'Whiplash' is injury to ligaments, muscles, and nerves of the neck and upper spine that usually results from a sudden backward movement of your head. The most common cause of whiplash is a car accident, especially when hit from the rear.

Work-related injuries can include accidents on the job, or exposure to harmful substances, as well as problems caused by working at a computer all day.