Introduction
Muscles, bones and joints that allow flexibility of movements provide the supportive framework of human body. Muscles carry out all movements, as they are composed of tissues that can contract.
There are two types of muscles- voluntary and involuntary. Voluntary muscles, such as those in your arms and legs are under conscious control and contract only when brain signals are sent to them via central nervous system. For example, if you want to bend your elbow, your brain instructs biceps muscles to contract, while during straightening of arm brain signals your biceps muscle to relax and instructs your triceps muscle to contract. Involuntary muscles such as those that are in your heart and digestive tract, normally function without your conscious control, under influence of autonomic nervous system.
Muscles form a sort of covering, protecting underneath it various structures like blood vessels, nerves, bones etc. Muscular disorders like cramps, tendonitis (as in tennis elbow), fibromyalgia, atrophy are common.
The 206 bones of your skeleton serve mainly as support system providing rigid internal framework. In addition, some bones also provide protection for certain vulnerable internal organs. For example, skull protects brain, rib cage shields lungs and heart and forms a protective covering over upper abdominal organs like liver and kidneys, pelvis shields bladder and portion of genital tract.
Bones are composed of living cells embedded in a dense framework of protein (collagen), saturated with minerals chiefly calcium and phosphorus. This framework partially acts as a storage and supply center for these minerals. Inside some bones, is a soft core, the marrow that manufactures blood cells. Each joint is complicated structure bound together on outside by fibrous bands called as ligaments. Inside each ligament, is a capsule made of fibrous tissue surrounding joint. The capsule is lined on inside by a thin membrane called synovium that continuously produces tiny amounts of fluid that lubricates joint. The surfaces of bone ends are covered by smooth, flexible cartilage. There are several different types of joints in your body. For example hinge joint (finger joints), ball-and-socket joint (shoulder joint) etc with some having little or no movement such as vertebral joint, while some have wide range of movement like shoulder joint.
Common disorders affecting bones and joints are- Osteoporosis, ankylosing spondylitis, arthritis, spondylosis, frozen shoulder etc increasingly observed in day-to-day life. In degenerative diseases like osteoarthritis, joint space between two bones is reduced. Diseases of marrow mostly affect blood. In severe cases of anemia, marrow examination is done to establish the diagnosis. Collagen is also an important component of connective tissue present all over body. Connective tissue diseases can affect virtually all body systems. While joint areas are frequently affected, very little destruction of bones and cartilage occurs. Cause of these diseases are unknown hence called “Autoimmune disease” with systemic lupus erythematous (SLE) commonest of them. Muscles, bones and joints are all more susceptible to damage from injuries than most other body parts. Muscle strain (tear), sprain (ligament tear), fractures, and dislocations, sports injuries are common form of injuries damaging muscles, bones and joints involved.
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