A bursa is a closed, fluid-filled sac that works as a cushion and gliding surface to reduce friction between tissues of the body. The major bursae (this is the plural of bursa) are located next to the tendons near the large joints, such as in the shoulders, elbows, hips, and knees.

Where are the most common bursae located?

Knee bursae

Bursitis occurs when bursae become inflamed. The most common locations for bursitis are in the shoulder, elbow and hip. But you can also have bursitis by your knee, heel and the base of your big toe. Bursitis often occurs near joints that perform frequent repetitive motion.

How many bursae are there in the human body?

There are more than 150 bursae located in your body. You're most likely to develop bursitis in joints you use over and over in the same way or in places you put a lot of pressure such as: Shoulders (subacromial bursitis).