There are approximately 160 bursas in the body. A bursa is a small fluid-filled sac lined that provides a cushion between bones, tendons and/or muscles around a joint. The bursa helps to reduce friction between the bones and allows free movement. Bursitis is inflammation in the bursa. Most commonly, bursitis is due to infection, repetitive movements, and excess pressure. The hips, shoulders, elbows and knees are the most commonly affected regions. Bursitis can be treated with anti-inflammatory medications and typically respond very well to steroid injections. On rare occasions, patients develop chronic bursitis that does not respond well to anti-inflammatories. In these cases, surgery is an option.