A joint is a part of the body where bones can bend or move around. Joints allow our bodies to be more flexible – for example, imagine what a problem it would be to walk if the joints of your legs (hips, knees, ankles and toes) did not move.
Joints are made up of bones and what are known collectively as ‘soft tissues’ - muscles, tendons, cartilage and ligaments. These soft tissue structures are important in keeping the joint stable, preventing the bones from falling away from each other.
Any part of a joint can become damaged or inflamed – situations giving rise to joint pain, joint stiffness or muscle pain.
Muscles are a type of body tissue with the unique ability of being able to contract or shorten its length. There are 3 types of muscles in our body:
- Muscles found attached to bones and together with our skeleton, forms our basic body structure. These are called skeletal muscles
- Muscles found in ‘soft’ areas of the body such as our intestines, bladder or in blood vessels. We are not usually aware of these muscles, known as ‘involuntary’ or ‘smooth muscles’
- Lastly, the bulk of our heart is made from muscle cells known as cardiac muscles
Skeletal muscles are the most obvious muscles in our body. They are connected to bones by a very strong tissue known as a tendon. When skeletal muscles contract, they shorten their length and in doing so, pull on tendons which in turn pull on bones. This is how we are able to move the bones in our body.
Bones are the very hard parts of our bodies, made largely of calcium, and form our skeleton. We have 206 bones:
- Some of these are held together very firmly and don’t move, such as the bones in our skull
- Some of these are large or long bones, such as the thigh bone
- Some are much smaller, for instance, each of our wrists contain 8 bones
Bones are important as they provide the basic support structure of our body. Together with muscles, bones allow us to stand, sit, walk and many other things we take for granted. Without bones, we would not be able to live on land – just look at the jellyfish!
The ligament is the substance which connects bones together. Think of ligaments as strong threads which anchor firmly onto the ends of bones. Ligaments can hold bones very closely together preventing or severely limiting movement – an example of this is the skull.
In other joints, ligaments connect the bones more loosely, enabling the joint to move around quite a bit. A good example of this is the shoulder joint which has a remarkable degree of movement – just swing your arm around in a circle to see the degree of freedom it has.
Although ligaments are important for connecting bones, the muscles around joints also play a big part in keeping a joint stable. For example, the bones of the shoulder are kept together because the muscles in the shoulder form a firm supporting structure of soft tissue – this makes the joint strong, but very mobile, as we have seen above.
It is because of this that injuries to joints can affect ligaments as well as muscles around the joint.
Cartilage is a substance which is found in many parts of the body. The tip of your nose and your ears are made from cartilage. Cartilage is also found inside joints, lining the surface of bones. This lining is important as cartilage provides a smooth surface within the joint so that, as bones move, they do not ‘rub’ into each other causing damage.
This smooth working of a joint is assisted in many of the more freely moving joints of the body by a type of fluid called synovial fluid. This is secreted by the synovium – a type of tissue found within the joint.
The synovium helps to form what is known as the ‘joint capsule’ – a structure enveloping the ends of the bones, cartilage, involving ligaments, tendons and muscles around the joint.
Damage to cartilage is one of the major causes of joint pain. This damage can arise as a result of ‘wear and tear’ of the joint as in osteoarthritis or through a number of forms of inflammation, such as with rheumatoid arthritis.
Pain in muscles and joints can arise as a result of a variety of causes, the most common of which are summarised below. Follow the links to read more information:
- Muscle pain. Pain or stiffness in muscles can have a variety of causes – from bad posture, unusual physical activity such as impromptu visits to the gym, or after hours spent in front of the computer. Sometimes, muscle pain can be the result of a condition known as fibromyalgia
- Joint pain. This arises as a result of some form of inflammation within a joint, which is generally referred to as arthritis. Two forms of arthritis are described and joint pain may arise from both – osteoarthritis (‘wear and tear’ of a joint) or rheumatoid arthritis
- Joint sprains and strains. Sprains and strains are generally acute (sudden) injuries to joints. The ankles, knees, wrists and shoulders are the most commonly affected. Joint sprains and strains are, more often than not, as a result of sporting injuries. Occasionally, the root cause or injury is not obvious
- Muscle strains. This is another form of sporting injury. Muscle strains can be mild and resolve quickly, or severe, where large tears in the muscle tissue can be seen, requiring surgery
- Back Pain. This is said to be one of the most common causes of time off work in the Western world. The term ‘back pain’, in general, refers to pain in the lower back. Symptoms can be mild, severe or incapacitating with the pain experienced mainly in the bottom of the spine (low back pain) or middle of the spine
- Neck Pain. In many ways, neck pain is similar to low back pain as described above except that it is the muscles, ligaments and joints of the neck which are involved. Neck pain or a stiff neck is a common experience – both in the young and old
- Rheumatism. This is a general term used to describe pain in the joints and surrounding muscles arising without an obvious cause. More often used by the older generation, the term rheumatism covers a wide variety of conditions involving muscles, tendons, ligaments and joints, all of which have one thing in common – inflammation
- Bruising. This is when blood collects under the skin or in deeper tissues such the muscles. Most often bruising occurs as a result of injury – a fall, knocking your thigh against a table or following a sports injury. The most common symptom of bruising is a discolouration seen through the skin. In severe cases however, a swelling may also be seen