Bursitis and Tendinitis

Paul Pellicci

Richard R. McCormack

BURSITIS

I. ANATOMIC CONSIDERATIONS

A bursa is a closed sac that contains a small amount of synovial fluid and that is lined with a cellular membrane similar to synovium. Bursae are present in areas where tendons and muscles move over bony prominences; these structures facilitate such motion. Approximately 160 formed bursae are present in the body, and others may form in response to irritative stimuli. Descriptions of the clinically important bursae follow.

Shoulder
- The subacromial bursa lies between the acromion and the rotator cuff.
- The subdeltoid bursa lies between the deltoid muscle and the rotator cuff.
- The subcoracoid bursa lies at the attachment of the biceps, coracobrachialis, and pectoralis minor tendons to the coracoid process.
Elbow
- The olecranon bursa lies over the olecranon process.
- The radiohumeral bursa lies between the common wrist extensor tendon and the lateral epicondyle.
Hip
- The iliopsoas bursa may communicate with the hip joint and lies between the hip capsule and the psoas musculotendinous unit.
- The trochanteric bursa surrounds the gluteal insertions into the greater trochanter.
- The ischiogluteal bursa separates the gluteus maximus from the ischial tuberosity.
Knee
- The prepatellar bursa lies between the skin and the patellar tendon.
- The infrapatellar bursa lies deep to the insertion of the patellar ligament.
- There are many popliteal bursae. The largest bursa lies between the semimembranous muscle and the medial head of the gastrocnemius muscle.
- Thepes anserine bursa lies between the medial collateral ligament and the sartorius, gracilis, and semitendinosus tendons.
Foot
- The Achilles bursa separates the Achilles tendon insertion from the posterior aspect of the calcaneus.
- The subcalcaneal bursa is located at the insertion of the plantar fascia into the medial tuberosity of the calcaneus.

II. ETIOPATHOGENESIS

Direct trauma to a bursal area may lead to an inflammatory response in the bursa, with its attendant hyperemia and the exudation of fluid and leukocytes into the bursal sac. Bursal fluid can be clear, hemorrhagic, or xanthochromic.
Chronic overuse or irritation of a bursal area.
A systemic disorder, such as rheumatoid arthritis (RA) or gout. In this case, the bursal fluid can be cloudy or purulent, depending upon the level of inflammation.
Septic bursitis may occur secondary to puncture wounds, from trauma, or to an overlying rash, such as psoriasis, a surrounding cellulitis, or after a local therapeutic injection. The organisms most frequently responsible are staphylococci (Staphylococcus aureus and Staphylococcus epidermidis) and streptococci.