What it means
Bursae are thin, slippery sacs that help tendons, muscles and skin glide over bone. There are many around the shoulder, hip, knee and elbow. Normally they hold so little fluid that they are barely visible. When a bursa is irritated, its lining thickens and fluid collects, so MRI or ultrasound shows a fluid-filled pocket. Common causes are overuse, pressure, a nearby tendon problem or an injury.
When it matters
Bursitis is common and often settles with rest, less pressure on the area and time. A thin layer of bursal fluid on a scan does not always cause pain, so doctors match it to where you hurt. At the shoulder and hip it often goes with tendon wear. Less often, a bursa becomes infected or inflamed by gout or rheumatoid arthritis, mostly at the elbow or knee. Then fluid may be drawn off for testing.
Questions to ask your doctor
- Could this bursitis explain where my pain is?
- Is a tendon problem nearby causing it?
- Is there anything to suggest infection or gout?
