Overview
Bursitis is inflammation of a bursa, a small fluid‑filled sac that reduces friction between tissues. It commonly affects the shoulder, elbow, hip, and knee.

Causes and risk factors
Repetitive motion, prolonged pressure, injury, and inflammatory conditions can trigger bursitis. Infection can also cause septic bursitis.

Symptoms
Localized pain, tenderness, swelling, and reduced motion near the affected joint.

Diagnosis
Clinical exam is typical; ultrasound or MRI may be used if the diagnosis is unclear or infection is suspected.

Treatment
Rest, activity modification, ice, NSAIDs, physical therapy, and sometimes corticosteroid injection. Septic bursitis requires antibiotics and drainage.

When to seek care
Persistent swelling, severe pain, or fever should be evaluated.