Ultrasound evaluation of bursae: anatomy and pathological appearances

Abstract

A bursa is an extra-articular sac that may communicate with a joint and functions to decrease friction between tendons and either bone or skin. Bursae can be classified as native and non-native (adventitious) bursae. The native bursae are lined with a synovial membrane and occur at predictable anatomical sites; knowledge of these normal structures can help distinguish them from other pathological entities. An adventitious bursa can form at sites of friction rather than at predictable anatomical sites, but otherwise have imaging features similar to native bursae. Bursal distention can occur from many pathological processes, most commonly resulting from chronic overuse injury. When imaging bursal pathological conditions, there is often an overlap of imaging findings, regardless of the cause. In general, ultrasound of a distended bursa reveals a fluid collection with either simple anechoic or more complex hypoechoic fluid. Bursal distention is characteristically unilocular and compressible, unlike other structures such as ganglion cysts, which are usually multilocular and non-compressible. This article reviews the anatomical locations of common bursae and shows pathological examples using ultrasound. Knowledge of typical locations and imaging appearances of bursae can aid in narrowing the differential diagnosis and guiding further management and treatment decisions.

Increased frequency of intermetatarsal and submetatarsal bursitis in early rheumatoid arthritis: a large case-controlled MRI study

“…In the plantar subcutaneous fat of the forefoot SMB was scored as sharply demarcated submetatarsal areas of contrast enhancement with or without rim enhancement that may develop secondary to mechanical loading [ 17 ]. These non-native (adventitious) bursae form at sites of friction but have imaging features similar to native bursae [ 29 ].…”

Recalcitrant Lateral Premalleolar Bursitis of the Ankle Associated with Lateral Ankle Instability

“…A bursa is a cyst lined with synovial cells and is usually located over a bony prominence to reduce friction with subcutaneous tissues or tendons [ 6 ]. Bursae are divided into two types by etiology.…”

Combined bursal aspiration and corticosteroid injection for rotator cuff tear patients unresponsive to conservative management

“…This sac is separated from the glenohumeral joint by the rotator cuff. [ 1 , 2 ] SASD bursitis is characterized by bursal distension caused by excessive synovial fluid accumulation in the bursa. [ 1 ] This distended bursa commonly results from rotator cuff tears.…”

“…[ 6 , 7 ] However, the potential use of aspiration in the management of rotator cuff tear-associated bursal fluid accumulation tends to be underestimated. [ 2 ]…”