musculoskeletal system disease

disorders of joints

Figure 1. Joints are well lubricated by synovial fluid (1) produced by a synovial membrane (2). Around many joints pass tendons (3) which are protected from rubbing and excess friction by strategically sited sacs or bursae (4), which are similarly lined and lubricated. Local damage, overuse or pressure can lead to inflammation and excess production of lubricating fluid (bursitis). Water on the knee, or housemaid's knee, is typical. Trigger finger and frozen shoulder are often due to synovitis, while tennis elbow results from damage at the attachment of a tendon. To avoid further strain the joint should not be overused but exercised gently; immobilizing it can lead to stiffness and may be harmful.

slipped disc

Figure 2. The spinal column (A) is a series of bones (B) surrounding the spinal cord (1) and separated by discs or cushion-like pads (2). These may slip out of their normal place if the surrounding ligaments tear due to strain or degenerative changes. The disc between fourth and fifth lumbar vertebrae (3) here protrudes towards the back of the vertebrae. Pain, spasm of the muscles and restricted movement are common results. The fifth lumbar vertebrae (C) (from above) shows the nerve roots (4) leaving the spinal cord. The position of the normal disc (5) is shown (pale), while the herniated disc (6) is seen pressing on the nerve root.


Figure 3. Arthritis means inflammation of the joints. In rheumatoid arthritis (A) the synovial membrane (1) becomes inflamed and thickened and produces increased synovial fluid within the joint (2). The capsule and surrounding tissues (3) become inflamed, while joint cartilage is damaged (4). Peripheral joints, as in the feet and hands, are involved. Blood tests reveal the presence of rheumatoid factor (RF) and the rate of red-cell sedimentation in a test-tube rises. Osteoarthritis (B), a degenerative disease, involves thinning of cartilage (5), loss of joint space (6) and bone damage (7). Heavily used or weight-bearing joints are affected. Blood tests are normal.

fracture of the femur

Figure 4. Fractures of the neck of the femur (A) are common in old people, who have quite brittle bones. The X-ray shows how pin and plate surgery (B) to the broken fragments can help to speed healing and recovery. The bones of young people break less easily than those of old people and when they do break they often cause less damage to surrounding tissue.


Figure 5. A hernia, often called a rupture, is the passage of any organ into an abnormal site. Common are those where the bowel (1) slides into the groin (2). A weakness develops in the abdominal muscle. A loop of bowel insinuates itself along the path of the spermatic cord in the male and appears as a bulge in the groin. Such an inguinal hernia may be controlled by a truss or can be treated surgically.

sports injuries

Figure 6. In sports such as football, undue stress may be put on bone, tendon and muscle, and physical fitness is essential to minimise the possible risks. Shown here are the different kinds of damage that the various parts of the body suffer from. Sudden movements and collision result in dislocated joints or broken bones in the shoulder, the arm and the leg. Cartilages in the joints may be displaced, while muscles and tendons are strained or torn.

The skeleton is the framework on which the body is hung and supported, and the muscles provide movement. Considering the extent of movement in life, and the weight that is supported, it is not surprising that disorders of the musculoskeletal system occur. However, not all disorders are the result of wear and tear; inherited disorders may also occur, others may arise spontaneously during life.


Wear and tear in muscles

The wear and tear disorders are among the most common. Everyone suffers muscular aches and pains at intervals and severe and unaccustomed exercise usually leads to discomfort and stiffness in the muscles the next day. In due course such exercise of muscle will lead to the development of more powerful muscles. In the untrained, sudden movements will commonly lead to muscles strains, tears of parts of the muscle mass, or tears in the tendons which attach muscles or bones. Such tears are often accompanied by bruising in the muscle, and healing can take two to three weeks (Figure 1).


Lumbago, or lower back pain, may follow muscle strain which results from unaccustomed activity such as digging. When back pain is accompanied by pain going down the back of one leg the condition is known as sciatica. Here the pain is due to pressure on one of the nerve roots that leave the spinal cord and supply the leg via the sciatic nerve. Treatment involves rest in bed on a firm mattress supported by wooden boards. The strain may be on one of the ligaments that run up the spinal column and support the vertebrae.


A weakness in the ligaments can allow the disc or pad which cushions each vertebra from the next to slip from its normal site and press upon the nerve pool. Treatment of a slipped disk requires rest while the tear heals and the disk returns to its normal place. If rest does not achieve this, surgical removal of the protruding portion of the disk may be necessary to alleviate symptoms (Figure 2).


Other sites at which injury can occur are in the joints between the bones. Bone ends are covered in cartilage and held together by strong fibrous capsules. The capsule of a joint may be torn, and the cartilage may be damaged. In the knee, specialized half-moons of cartilage act as cushions between the femur (thigh bone) and the tibia (shin bone). These two cartilages in each knee are attached to the edge of the wearing surface of the knee joint. Sudden twisting movements of the knee may be enough to dislodge a cartilage, tearing its attachment to the bone. This is painful, prevents full use of the knee, and if it does not settle the offending cartilage may have to be removed. Cartilage injuries are common in sports in which weight-bearing joints are frequently twisted.


Arthritis and its treatment

Over the years the degree of wear and tear becomes excessive and consequence may be the premature development of osteoarthritis, also known as osteoarthrosis,in the joints. This type of arthritis develops in many elderly people in the ankle, knee, and hip. The results are that the joint narrows, movement is restricted and pain and deformity occur. Osteoarthritis in the hip can be the most disabling, but it is now possible to replace the hip joint with metal and plastic substitutes and thus restore full mobility.


rheumatoid arthritis in the hand
The hands are common sites of rheumatoid arthritis. An X-ray shows the typical deformity of the joints and the deviation of the fingers towards the little finger side. The causes of rheumatoid arthritis (not clearly defined) may include infection, hereditary factors, emotional disturbances and physical overuse of the affected part. Treatment may involve the administration of anti-inflammatory drugs.


The other common arthritis, known as rheumatoid arthritis, is not a result of overuse. Women are more likely to be affected than men. The small joints of the hands and feet become damaged and deformed, and elbows, shoulders and ankles are also affected. The disorder is sometimes part of a more generalized body disturbance, and evidence of widespread inflammation can be detected in blood tests. In both types of arthritis, symptomatic treatment for the pain with analgesics is beneficial, but suppression of the inflammation may be required in rheumatoid disease. This is often achieved by administering other drugs (Figure 3).


Some musculoskeletal disorders are congenital, that is, present from birth; for example, congenital dislocation of the hip is sometimes found in infants. The hip joint does not form fully for many years after birth, and initially the socket in which the ball of the femur is held is very shallow. It is quite easy to dislocate the head of the femur from the socket. In a few children this occurs spontaneously and, if not corrected, will cause maldevelopment of the hip. Treatment is simply to splint the legs so that the joint is held correctly and cannot dislocate. Although ungainly, such treatment at an early stage is effective. The longer that diagnosis is delayed the more difficult is the cure and babies are examined shortly after birth for evidence of this uncommon condition.


congenital dislocation of the hip
Congenital dislocation of the hip is a condition found at, or shortly after, birth. It is due to an increased ability of the head of the femur to slip out of the developing socket in the pelvic bone. In this X-ray, the joint on the left is normal, the one on the right displaced. Characteristic clicking of the hip is checked for in the weeks after birth.


Treatment by immobilization

Immobilization of an injured part of the musculoskeletal system can be required for many different troubles, such as fractured bones (Figure 4). Plaster of Paris casts may be adequate if the parts of the bones are well aligned. Otherwise internal fixation can be undertaken, in which the bones are held together with pins or plates screwed into the fragments. It is important at every stage after the operation, including the period during which to exercise as much as possible, because during the enforced rest much wasting of the unused muscles will have occurred. This can considerably slow a full recovery, for building up muscles always takes time, effort and dedication.


Muscular dystrophies are inherited degenerative diseases that cannot be cured. The Duchenne type affects the pelvis, shoulders, trunk and later the limbs. The disease is first noticed as the child learns to walk with a characteristic waddling gait. He falls frequently and has difficulty in climbing stairs and rising from a sitting or lying position. A wheelchair becomes necessary. The facioscapulo-humeral type affects the face, shoulders, trunk and finally the legs.