Bursitis is a painful condition that results from the inflammation of a bursa, otherwise known as a bursa sac. The inflammation may be limited to a single bursa or include multiple bursae (the plural of bursa) at the same location. Bursitis may be a repetitive stress injury, the results of an injury or even an infection
The bursa sac is a small sac made up of synovial tissue, a slick substance the body uses to provide a slippery surface for things like tendons to slide against without friction. The bursa sac is filled with synovial fluid, a slippery and viscous fluid (similar in consistency to egg whites) that allows the bursa sac to move against itself with very little friction.
The bursa acts as a slippery cushion at your joints and areas of your body where motion causes one part of your anatomy to rub against another. Anatomy such as tendons, ligaments, skin, muscles and bones are protected from irritating each other when they rub together by these cushions of bursa sacs. Like the end of a bone at a joint rubbing against the muscle next to it when you flex the joint, the bursa provides a gliding surface between the two that reduces the friction, and therefore lessens the irritation, that would occur with the rubbing.
A healthy bursa creates a very low friction surface between the two parts of your body rubbing together. However repetitive rubbing, acute or cumulative trauma, or other factors can irritate the bursa. And like most any other part of your anatomy if it becomes irritated it becomes inflamed. When the bursa is swollen and tender from the inflammation, pressure and movement across it can be quite painful and that is bursitis.
The anatomical features that rub across the inflamed bursa can further irritate it, and you will often find the movement of those features to be painful and difficult. Furthermore other anatomical features that do not use the bursa directly, but may contact it (like a tendon) can further irritate the bursa when they are moved.
Bursitis often the result of repetitive stress, though that repetitive stress is not always repetitive motion. Holding a joint in such a way that constant and unbalanced pressure is placed on the bursa can irritate it as well. Similarly bursitis often develops after an injury or a period of overuse of a given joint. Bursitis can be the result of an infection or a complication of another medical condition such as arthritis or gout.
Know More: Causes of Bursitis
It is a common occurrence for bursitis to develop along with tendonitis. Even though both conditions present with unique symptoms, if they develop together it may be difficult to properly diagnose and treat your bursitis and/or tendonitis.
Know More: Diagnosing Bursitis
And now a bit of information for your trivia bag, bursa is Latin for purse.