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ARTHRITIS FOUNDATION OF VICTORIA
www.arthritisvic.org.au  ... (Copy reviewed 2005)

ARTHRITIS - WHAT IS IT

Definitions

The word arthritis comes from Greek:  arth- = joint and -itis = inflammation.

So, arthritis really means inflammation of the joint.

However, arthritis is not a single condition. There are well over 100 kinds of arthritis, all of which affect one or more joints in the body, and some of these forms of arthritis don't involve any inflammation.

Perhaps it is more useful to think of arthritis meaning problems with the joint!

What Can Go Wrong in a Joint?

The various forms of arthritis are part of a  group of diseases called "musculo-skeletal" disorders.

These conditions affect bones, muscles and joints, for example:

• Disorders of bone:
  • e.g. osteoporosis
• Disorders of muscle:
  • e.g.  polmyosotis, polymyalgia rheumatica
• Disorders of joints:
  What can go wrong in joints?
  • the cartilage can degenerate
    • osteoarthritis,
  • the joint lining can become inflamed
    • rheumatoid arthritis
  • the joint fluid can become inflamed
    • gout, infection

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The Anatomy of a Joint

Click onto a label for more information

A joint is a meeting of two bones so that movement can occur.

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Parts of a typical joint:

Cartilage

This is a strong, smooth material which forms a cushion at the end of each bone in a joint. It absorbs shock and prevents bone from rubbing against bone. If the cartilage is damaged or degenerates, osteoarthritis can occur.

Synovial Membrane

This membrane encloses the synovial sack, filled with a lubricating fluid which protects and lubricates the joint. Synovitis occurs when this membrance becomes inflamed, and is typical of rheumatoid arthritis. An infection can also cause inflammation in the synovial fluid. The deposit of crystals in the synovial fluid is a characteristic of gout.

Bursa

This is a small lubricating sac which is not actually part of the joint but which lubricates the movement of muscle over muscle and of muscle over bone. The bursa can become inflamed causing bursitis.

Muscle

The muscles move bones by contracting and expanding. In conditions such as polymyalgia rheumatica, the muscles become inflamed.

Tendon

The tendon is a fibrous cord that attaches muscle to bone. Tendinitis is inflammation of the tendon.

Ligament

The ligaments are short fibrous cords that attach bone to bone, making up the joint capsule. A problem called enthesopathy occurs when ligaments become inflamed, as in ankylosing spondylitis.

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Forms of Arthritis

Dr James Fries has developed eight categories of arthritis which help understand how arthritis affects different structures of the body. His book "Arthritis, A Take Care of Yourself Health Guide" is highly recommended and is available through Arthritis Victoria. He is also the co-author, with Dr Kate Lorig, of the "Arthritis Helpbook" which is the basis of the Arthritis Self Management Course offered in community settings through Arthritis Victoria.

For more detailed information on the categories or on the specific conditions, click on the blue text.

The Eight Categories

  Date Last Reviewed by NEVDGP: 20 August, 2006