Bursitis

Bursitis is painful swelling in a small, fluid-filled sac called a bursa. Bursae (the plural of bursa) cushion spaces around bones and other tissue. They’re like bubble wrap that protects structures throughout your body. Bursae cushion the spaces between bones and your:

• Muscles.
• Tendons.
• Skin.

Bursitis happens when a bursa becomes irritated and swells. The most common causes of bursitis are overuse and putting too much pressure on a bursa. The pain from an inflamed bursa may develop suddenly or build up over time.

Types of bursitis

There are more than 150 bursae in your body. Bursitis can affect any of them. You’re most likely to develop bursitis in joints you use for repetitive motions or in places you put a lot of pressure, including your:

• Shoulders (subacromial bursitis).
• Elbows (olecranon bursitis — sometimes called miner’s elbow or barfly’s elbow).
• Knees (prepatellar bursitis — housemaid’s knee).
• Feet (especially near your heel, big toe or the ball of your foot).
• Hips (iliopectineal or trochanteric bursitis).
• Butt (ischial bursitis or weaver’s bottom).

Healthcare providers might refer to different types of bursitis with a specific name, but they’re all the same issue — swelling in and around a bursa.