Every person has hundreds of bursa found throughout the body. The function of a bursa is to decrease friction between two surfaces that move in different directions. The bursa is a slippery, fluid-containing sac. Normally, the bursa is thin and contains a small amount of fluid.
A bursa is found where there is movement of a joint causing two tissues to rub against each other. For example, behind the elbow or in front of the knee, there is a bursa to allow the skin to move without rubbing against the bone. These movements should be smooth and effortless.
Bursitis - Inflammation of the Bursa
Under normal circumstances, the bursa provides a slippery surface that has very little friction with movement. Bursitis means that the bursa has become inflamed. The bursa loses its gliding capabilities, and becomes more and more irritated when it is moved.
When the condition called bursitis occurs, the normally slippery bursa becomes thickened and swollen. The added bulk of the swollen bursa causes more friction within an already limited space. Also, the smooth gliding bursa becomes gritty and rough. Movement of an inflamed bursa is painful and irritating.
Causes of Bursitis
Bursitis usually results from a repetitive overuse injury or due to prolonged and excessive pressure. Overuse injuries are most often seen in patients with bursitis deeper inside the body. Bursitis from excessive pressure is most often seen in superficial types of bursitis, such as people who kneel or rest on their elbows.
The next most common cause of bursitis is an acute injury, such as a contusion. Often a blunt trauma causes swelling within the bursa. The bursa, which functioned normally up until the time of trauma, begins to develop inflammation, and bursitis results. Once the bursa is inflamed, normal movements and activities can become painful.
Systemic inflammatory conditions, such as rheumatoid arthritis and gout, may also lead to bursitis. These types of conditions can make patients susceptible to developing swelling and inflammation within the bursa.
The last major cause of bursitis is infection. An infected bursitis, also called a septic bursitis, occurs when there is infection within the bursa. There is usually a break in the skin over the bursa that causes the infection, but there can also be infection spread to the bursa from within the body. Septic bursitis requires the use of antibiotics for treatment.