ABSTRACT
There are approximately 160 discrete bursae in the human body. Most true bursae form during embryonic development, though some, such as the olecranon bursa, may develop later in life.1 Adventitial bursae also form later in life in response to repeated trauma, constant pressure, or friction. While anatomic/true bursae are lined with epithelial cells and contain synovial cells that secrete lubricating uid rich in collagen and proteoglycans, adventitial bursae lack endothelial cells and do not secrete or contain synovial uid. Most of the bursae described in this chapter are anatomic/true bursae. Examples of adventitial bursae include those that form over a bunion or over an osteochondroma.
