The Basic Function of a Joint

It’s estimated that there are between 250 and 350 joints in the human body. This number varies depending on, for example, whether you view the skull as one solid structure or consider the jigsaw pieces that fit together to form it as being linked by joints.

But let’s not be so pedantic. If a joint is an area where two bones oppose each other for the purpose of motion of a body part, there are probably still close to 230 joints in the human body – which is a lot!

The basic function of any joint is to allow for movement. Joints form ‘links’ between bones so that the skeleton is an articulating rather than a rigid structure. The joint is the actual space between two bones, and in order for movement to occur at the joint there has to be action of the surrounding soft-tissue structures. These soft-tissue structures include:

Ligaments, tough elastic bands of connective tissue that attach bone to bone and prevent excessive movement between the bones.

Tendons, also a type of connective tissue that attaches muscle to bone, so that when the muscle contracts, tension is exerted onto the tendon causing the joint to move.

The bursa, a fluid-filled sac between bones and ligaments, or other adjacent structures, that helps cushion the friction created within and around the joint by repetitive movement.

It is therefore clear that joints are complicated structures. As mentioned above, the key function of all joints is to enable movement. With any moving part, however, there is the potential for wear and tear, and the joints of the human body are no different.


By far the most common cause of joint damage (or joint ill health) is excessive wear and tear which results in degeneration of the structures around the joint, i.e. the cartilage, ligaments and tendons. Wear and tear is caused by three things – trauma (twists, sprains and strains, whiplash, etc.), repetitive strain (repeated movements over a long period of time) and overuse (applying excessive strain on the joint).

Degeneration is a fact of life, unfortunately, and therefore cannot be avoided. However, the process can be managed by doing things that encourage joint health.


Fibrous joints. The opposing ends of the bones are attached only by fibrous connective tissue, e.g. the ‘gomphoses’ that hold the teeth into their bony sockets.

Cartilaginous joints. Here the opposing ends of the bones are attached by cartilage, e.g. the ends of adjacent vertebrae are attached by fibrous cartilage (the disc).

Synovial joints. By far the majority of joints in the body are synovial joints (e.g. hinge, pivot or ball and socket joints). These joints permit significantly more movement than the other types. They have a synovial capsule that surrounds the joint, a synovial membrane lining the inner part of the capsule, which also assists with joint lubrication, and a cartilaginous covering which protects the bony surfaces from rubbing up against each other.

The Basic Function of a Joint


1. Be kind to your joints

Ongoing repetitive strain and overuse will inevitably cause damage over time. Try to ensure that your posture is good (avoid slouching, check that your work station is ergonomically correct). If you train in the gym, warm up properly, stretch, make sure you are doing the exercises correctly, and ask your instructor for help or advice if necessary. Runners also need to make sure they warm up sufficiently.

If you are experiencing joint pain, your body (or your joint) is telling you it’s not happy! Simply suppressing the pain with anti-inflammatories or pain killers will speed up the degenerative process.

Remember, joint degeneration is accumulative and continues exponentially. I am always conscious of the words of so many of my older patients, ‘If I knew how my joints would be feeling at the age of sixty, I would have taken better care of them in my younger days!’

2. Diet

Our diet has a direct impact on all aspects of our health, including the health of our joints. The general consensus among nutrition gurus is that a diet low in (saturated) fat, with a moderate protein content and high in vegetables, fruit, legumes and grains, provides all the necessary building blocks for healthy connective tissue (ligaments and tendons) and cartilage.

The result of trauma, repetitive strain and overuse syndromes is inflammation. It is this inflammation that generates the pain signals. It is also well documented that diets high in the essential fatty acids (cold-water fish, sardines, pilchards, etc.) and flax seeds are anti-inflammatory.

3. Exercise

Exercising a stiff, achy and painful joint may be the last thing you feel like doing, but there is a growing body of research that supports its beneficial effects.

Exercise stimulates the production of endorphins, which make you feel great and reduce pain. The type of exercise will be different for everyone – varying from very mild stretching to more vigorous aerobic exercise.

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4. Nutritional supplementation 

The above three management modalities really fall into the preventive category. The degenerative process does continue, however, so the time will come when management will include treatment. Here nutritional supplementation has a vital role and is the fourth component of managing joint health.

Nutritional support needs to be aimed at the structures that make up the joint complex, namely the muscles, tendons, ligaments, bones and cartilage.


Proteins are the building blocks of muscles. An increased intake of plant protein (soya, beans, nuts and seeds) is recommended, and in specific cases a protein supplement may be required.

Tendons and ligaments are made up of densely packed collagen fibres, also called connective tissue. Because of the fibrous nature of these structures they are not well supplied with blood, which often retards the healing process. However, supplementation with collagen has been shown to stimulate connective tissue rehabilitation. Cutting-edge nutrition research is now also highlighting the beneficial effects of iso-alpha-acids in connective tissue health.


Glucosamine sulphate and chondroitin sulphate supplementation provides concentrated building blocks for cartilage formation (made of specific dietary sugars).

The Basic Function of a Joint

Other supplements that are beneficial in joint heath include:

  • Omega-3 fatty acids (1 000 – 1 500 mg per day, best in the EPA/DHA form).
  • Antioxidants. There are many antioxidant products on the market, with different formulations. Look for ones that include the powerful antioxidants vitamins A, E and C, phytonutrient complex, grape seed extract, alpha-lipoic acid and co-enzyme Q10. Reputable formulations are developed with the various nutrients in the correct ratios – follow the recommended dosage.
  • Vitamin C (1 000 mg per day).
  • Vitamin D (1 000 IU – cholecalciferol).
  • Calcium carbonate (800 – 1 000 mg per day). Calcium carbonate is the most common calcium supplement, but it is not the most bio-available. Other options include calcium citrate and calcium gluconate; however, higher doses are required.
  • Magnesium (400 – 500 mg per day). Again there are various sources, including magnesium oxide, ascorbate, bis-glycinate, etc. Taking a calcium/ magnesium combination will usually suffice, with the appropriate source and dosage.
  • Herbal anti-inflammatory nutrients, e.g. ginger and turmeric. These are best taken in supplement form to ensure that adequate quantities are ingested. You will find them, in the correct dosages and combinations, in the various herbal ‘joint formulas’ stocked by most health food stores and pharmacies.

Although our joints are complex structures and a certain amount of stress on them is inevitable, optimal management of their health will prevent accelerated degeneration. In addition to the measures described above, it may well be necessary to consult a chiropractor, osteopath, biokineticist or physiotherapist to assist with and speed up the rehabilitation of strained, sprained joints.

Editor's note: This article was written before we knew about egg-shell membrane. Please see my review on this here: Flexofend. There are other excellent articles on joint health such as Joint Health – the natural way.

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