Bursae are fluid-filled cavities located at tissue sites where tendons or muscles pass over bony prominences near joints, such as the knee. The function of a bursa is to facilitate movement and reduce friction between moving parts.
Review Date 7/25/2020
Updated by: C. Benjamin Ma, MD, Professor, Chief, Sports Medicine and Shoulder Service, UCSF Department of Orthopaedic Surgery, San Francisco, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.