&p.1:Abstract The authors present a re-view of the anatomy of the majorbursae around the shoulder joint anddiscuss the use of the different imag-ing modalities which demonstratetheir radiologic features. The calci-fied subacromial-subdeltoid bursahas a characteristic appearance onplain radiographs. When inflamed itcan be visualized by ultrasound andmagnetic resonance imaging. Calcif-ic bursitis may involve the subcora-coid bursa. This bursa may mimicadhesive capsulitis of the shoulder or

complete rotator cuff tear when in-jected inadvertently during shoulderarthrography. Less well known arethree coracoclavicular ligament bur-sae. These are also subject to calcificbursitis and have a typical radiologicappearance.

&kwd:Key words Shoulder bursitis ·Subcoracoid bursa ·Coracoclavicular bursa ·Subacromial-subdeltoid bursa ·Shoulder anatomy · Shoulderarthrography · Shoulder imaging&bdy:

Skeletal Radiol (1996) 25:513–517© International Skeletal Society 1996 R E V I E W A RT I C L E

Imaging of bursae around the shoulder joint&roles:Nathalie J. BureauRobert G. DussaultTheodore E. Keats

Introduction

The shoulder girdle is a relatively complex anatomicstructure. Its osseous and tendinous components are wellknown. The many bursae that accompany these compo-nents are less well recognized. Bursae are small poucheslined by synovium and normally contain a film of syno-vial fluid. Their purpose is to alleviate friction by creat-ing a space between two tightly apposed structures thatmove relative to one another.

These bursae may have clinical implications. With theadvent of cross-sectional imaging, it has become manda-tory for radiologists to expand their knowledge of softtissue anatomy. The purpose of this paper is to reviewthe anatomy of the major bursae around the shoulderjoint and to demonstrate the radiologic features of calcif-ic bursitis of these bursae.

Bursae around the shoulder joint

Subacromial-subdeltoid bursa

The subacromial-subdeltoid (SA-SD) bursa is actuallycomposed of two bursae, the subacromial and subdeltoid

bursae, which are contiguous in approximately 95% ofpatients [1]. The SA-SD bursa covers a large surface areaand facilitates movement between the rotator cuff ten-dons and the coracoacromial arch and between the rota-tor cuff tendons and the deltoid muscle. Medially it ex-tends to the coracoid process. Its lateral and inferior ex-tent beneath the deltoid muscle is more variable, and itmay extend 3 cm below the greater tuberosity of the hu-merus [2]. Anteriorly the SA-SD bursa extends to coverthe bicipital groove (Fig. 1).

The normal SA-SD bursa is a potential space and isnot visible on plain radiographs. Its inner layers consistof synovial tissue whereas its outer layers consist of con-nective tissue with a certain amount of fat interposed be-tween the rotator cuff tendons and the deltoid muscle.This extrasynovial fat may be seen on radiographs as aradiolucent stripe 1–2 mm wide [3] (Fig. 2A). Accordingto Mitchell et al. [4] the peribursal fat plane is better de-lineated on internal rotation views of the shoulder. Par-tial or complete obliteration of this fat stripe is not a spe-cific indicator of shoulder pathology. This fat plane canbe well demonstrated by magnetic resonance imaging(MRI). On MRI, fluid is not detected in the normal bur-sa. In the coronal plane the peribursal fat appears as a

Presented at the Annual Meeting of theCanadian Association of Radiologists,Montréal, QC, Canada, June 1995

N.J. Bureau, M.D. (✉)Department of Radiology,Hôtel-Dieu de Montréal Hospital,3840 St-Urbain, Montréal,Québec H2W 1T8, Canada

R.G. Dussault, M.D. · T.E. Keats, M.D.Department of Radiology,Health Sciences Center,University of Virginia, Charlottesville, Vir-ginia, USA&/fn-block:

stripe of high signal intensity on spin echo T1-weightedsequences (Fig. 2B). Kaplan et al. [5] have shown thatfocal obliteration of the peribursal fat line may be seen innormal subjects and usually occurs adjacent to the great-er tuberosity of the humerus.

The SA-SD bursa can be seen on plain films when in-volved by calcific bursitis, usually secondary to hydroxy-apatite crystal deposits [6]. Patients may present withacute symptoms of pain, tenderness on palpation, sur-rounding edema and swelling, or may be entirely asymp-tomatic. The cause and pathogenesis of this crystal depo-

sition disease are unknown. Calcification in the SA-SDbursa may present as a teardrop-shaped radiodense areaadjacent to the undersurface of the acromion (Fig. 3).Large amorphous tumoral-like calcific deposits may beseen in association with chronic renal disease.

Fluid accumulation in the SA-SD bursa may be seenwith rotator cuff tear, inflammatory or crystal depositiondisease, and with septic bursitis; the last is particularly aproblem in intravenous drug users. Ultrasound is a fastand easy method of evaluating joint effusion and pro-vides direct visualization for puncture and drainage.

Subcoracoid bursa

The subcoracoid bursa is located between the subscapu-laris tendon inferiorly, and the coracoid process and thecombined tendon of the short head of the biceps and thecoracobrachialis muscle superiorly [7] (Fig. 1). It ex-tends posteriorly beneath the coracoid process. It facili-tates movement by reducing friction between the sub-scapularis tendon and the tendons of the short head ofthe biceps and the coracobrachialis during the arc of ro-tation of the humeral head. The subcoracoid bursa maypresent as a calcific bursitis and should be recognizedby its typical location (Fig. 4). During shoulder ar-thrography, direct injection of the subcoracoid bursahas been reported as a cause of technical failure andmay be confused with adhesive capsulitis [8, 9]. In asmall percentage of patients, a natural communicationexists between the subcoracoid bursa and the SA-SDbursa. Hence, if not recognized, inadvertent injection ofthe subcoracoid bursa in such a patient would result ina false diagnosis of complete rotator cuff tear (Fig.5A, B).

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Fig. 1 The bursae around the shoulder joint: 1 subacromial-sub-deltoid bursa; 2 subscapularis bursa, located between the glenohu-meral joint capsule and the subscapularis muscle, usually commu-nicates with the glenohumeral joint and is considered by many tobe a capsular recess; 3 subcoracoid bursa; 4 coracoclavicular bur-sa, located between the trapezoid and conoid parts of the coraco-clavicular ligament; 5 supra-acromial bursa&/fig.c:

A B

Fig. 2A, B Normal peribursalfat. A Radiograph of the shoul-der in internal rotation demon-strates a crescentic radiolucentarea extending from the under-surface of the acromion to theouter aspect of the proximalhumerus (arrowheads). Thisrepresents fat layers adjacent tothe normal subacromial-subdel-toid bursa. B Coronal T1-weighted MR image shows theextension of the peribursal fatas a thin, crescentic hyperin-tense area (arrow) between thedeltoid muscle (D), the supra-spinatus tendon (S) and lateralmargin of the proximal humer-us (H). A acromion&/fig.c:

Coracoclavicular bursae

The coracoid process and the clavicle are connected bythe coracoclavicular ligament. This is composed of twofascicles: the conoid and trapezoid. In the angle betweenthe conoid and trapezoid parts of the coracoclavicularligament there is a quantity of fibro-fatty tissue frequent-ly containing a large bursa, referred to in most textbooksas the coracoclavicular bursa [10] but as the supracora-coid bursa by some authors. The coracoclavicular bursaintervenes between the clavicle above and the posterior

part of the superior surface of the coracoid below (Fig.1). Other smaller bursae can be found in relation to ei-ther the trapezoid or conoid fascicles. Calcific coracocla-vicular bursitis may be an incidental finding on roent-genography, and should be recognized by its typical lo-cation (Fig. 6A–C). It has also been reported as a causeof chronic shoulder pain [11, 12]. Calcification in the co-racoclavicular region may be the result of calcification ofintact or torn ligaments, but in contrast to the amorphous

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Fig. 3 Calcific subacromial-subdeltoid bursitis. Radiograph of theshoulder in neutral position shows amorphous calcifications ex-tending along the outer margin of the upper humerus and belowthe greater tuberosity (arrowheads) &/fig.c:

Fig. 4 Subcoracoid calcific bursitis. Radiograph of the shoulder inneutral position shows an oval, amorphous calcific deposit inferiorto the coracoid process (arrowhead) &/fig.c:

A

B

Fig. 5A, B Inadvertent injection of the subcoracoid bursa duringshoulder arthrography. A At fluoroscopy the contrast mediumflowed readily into what was thought to be the subscapularis bursa(black arrow). Then spontaneous communication with thesubacromial-subdeltoid bursa occurred (white arrowhead). Notethe absence of contrast in the glenohumeral joint. At this point asubcoracoid bursa injection was suspected and the needle was re-positioned. B The glenohumeral joint (arrowheads), confirmingintra-articular needle placement. Injection of the subcoracoid bur-sa during shoulder arthrography may mimic a complete rotatorcuff tear in the rare instance when the subcoracoid bursa commu-nicates with the subacromial-subdeltoid bursa&/fig.c:

appearance of calcific coracoclavicular bursitis, calcifi-cation of the ligaments will appear as streaks or lines inthe shape of the ligaments [13].

Supra-acromial bursa

The supra-acromial bursa is located on the superior as-pect of the acromion and normally does not communi-cate with the glenohumeral joint (Fig. 1) [14].

Other bursae about the shoulder

The glenohumeral joint capsule usually has two open-ings. One communicates with the subscapularis bursa(Fig. 1) [15] by the Weitbrecht foramen located be-tween the superior and middle glenohumeral ligaments.The second is the opening at the bicipital groove be-tween the humeral tuberosities for the tendon of thelong head of the biceps and its synovial sheath. A third,inconstant opening may occur posteriorly and connectsthe joint to a bursa that separates the infraspinatus ten-don and the joint capsule [16]. This unusual bursa is theinfraspinatus bursa. The subscapularis bursa and infra-spinatus bursa almost always communicate with theglenohumeral joint and although they are commonly re-ferred to as bursae, they are considered by many to bejoint recesses.

Conclusion

With the refinement of imaging modalities, it has be-come mandatory for radiologists to expand their knowl-edge of anatomy. Soft tissue structures that were former-ly demonstrated by contrast studies are now readily seen,and in much detail, with MRI and ultrasound. With thesemodalities, certain pathologic processes may have simi-lar appearances. For example, ganglion cysts may be dif-ficult to differentiate from inflamed bursae, and at timesmay be diagnosed solely on the basis of their anatomiclocation.

The subacromial-subdeltoid bursa is perhaps the mostfamiliar bursa around the shoulder joint and is frequentlyinvolved in pathologic conditions. Less well known arethe subcoracoid bursa and the coracoclavicular bursae,which may also present as bursitis and when calcifiedshould be readily diagnosed on plain films by their typi-cal location.

Knowledge of the soft tissue anatomy of these bursaeis necessary to avoid misdiagnosis and pitfalls in inter-pretation.

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A

B

C

Fig. 6A–C Coracoclavicular bursitis. Radiographs of the shoulder(A, B) and an antero-posterior coned-down view of the coracoclavic-ular area (C) in three different patients demonstrate examples of co-racoclavicular bursitis seen as collections of amorphous calcificationbetween the clavicle above and the coracoid process below (arrow)

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