Shoulder ultrasonography: performance and common findings

Abstract

Ultrasound (US) of the shoulder is the most commonly requested examination in musculoskeletal US diagnosis. Sports injuries and degenerative and inflammatory processes are the main sources of shoulder pain and functional limitations. Because of its availability, low cost, dynamic examination process, absence of radiation exposure, and ease of patient compliance, US is the preferred mode for shoulder imaging over other, more sophisticated, and expensive methods. Operator dependence is the main disadvantage of US examinations. Use of high range equipment with high resolution transducers, adhering to a strict examination protocol, good knowledge of normal anatomy and pathological processes and an awareness of common pitfalls are essential for the optimal performance and interpretation of shoulder US. This article addresses examination techniques, the normal sonographic appearance of tendons, bursae and joints, and the main pathological conditions found in shoulder ultrasonography.

Keywords: Anatomy; musculoskeletal imaging; shoulder; ultrasonography.

Figure 1

Bicipital groove (BG) and long head of the biceps brachii tendon. (a) Short axis image. The normal biceps tendon is a rounded echogenic structure (arrows) surrounded by a thin sonolucent area representing a small amount of fluid in the synovial sheath; the echogenic transverse ligament is seen superficial to the tendon. The bicipital groove (BG) is identified at the anterior aspect of the humeral head as a concave echogenic line. (b) The position of the transducer on the bicipital groove of the humerus. (c) Long axis image shows the fine fibrillar structure of the biceps tendon (arrows). (d) The position of the transducer along the humeral shaft to view the long head of the biceps tendon.

Figure 2

Subscapularis tendon. (a) Long axis view of the tendon. A fibrillar pattern is seen along the tendon (arrows), which inserts into the lesser tuberosity (LS). (b) The transducer is placed in an axial plane for a long view of the tendon. (c) Short axis view of the tendon shows a series of hyperechoic fibers and hypoechoic clefts, due to interposed muscle fibers among the tendon fibers (arrows). (d) The transducer is placed in a sagittal plane for a short view of the tendon.

Figure 3

Infraspinatous and teres minor tendons. (a) The infraspinatous tendon (arrow) is seen lying superficial to the echogenic cortical bone of the humeral head and deep to the echogenic bursal fat stripe. (b) The position of the transducer in an axial plane over the infraspinatus fossa.

Figure 4

Glenohumeral joint and spinoglenoid notch. (a) Glenohumeral joint. The image shows the humeral head (H) covered by the thin hypoechogenic articular cartilage (long arrow), the glenoid margin (G) and a homogeneously echogenic triangular structure- the fibrocartilagenous posterior labrum (short arrow). (b) The transducer is positioned slightly lower and medially in an axial plane. (c) Spinoglenoid notch. The image shows the suprascapular nerve together with the artery and vein running in this notch (arrow). (d) The transducer is moved slightly medially to view the spinoglenoid notch.

Figure 5

Supraspinatous tendon and dynamic maneuvers. (a) Long axis view of the supraspinatous tendon. The tendon has a homogeneous pattern of medium-level echoes and a convex beak-like shape. From superficial to deep, note the echogenic skin and subcutaneous fat, the hypoechogenic deltoid muscle, the echogenic fat stripe, the hypoechogenic fine subacromial-subdeltoid bursa (arrows) and the supraspinatous tendon lying over the hypoechogenic cartilage of the humeral head, the echogenic cortex of the humeral head and the greater tuberosity. (b) Position of the transducer, in a sagittal plane lateral to the bicipital groove. (c) Short axis view of the supraspinatous tendon (long arrows). The tendon lies between the humeral cartilage below and the subacromial subdeltoid bursa above (SASDB). Note the short axis view of the biceps tendon medially to the supraspinatous, appears as an oval echogenic structure (small arrow). (d) Note the position of the transducer in the axial plane. (e) Dynamic scanning. Left plot shows Supraspinatous tendon and subacromial bursa (arrow) lateral to the acromion (A) Right plot: During dynamic maneuvers, the supraspinatous tendon and subacromial bursa are scanned while gliding beneath the subacromial space (A). (f) The transducer is positioned over the acromion while the patient raises his/her arm. (g) The patient extends the arm forward.

Figure 6

Acromioclavicular joint. (a) The medial edge of the acromium (A), clavicular edge (C) and joint capsule (arrows) are seen. (b) The transducer is positioned in a coronal plane, over the acromion.

Figure 7

Complete full thickness tear of the supraspinatous tendon. Tendon nonvisualization in a patient with completely retracted tear (arrows).

Figure 8

Full-thickness tear. The image shows a sonolucent defect (arrows) extending across the width of the supraspinatous tendon. The tendon is nonretracted and visualized on both sides of the tear.

Figure 9

Minimally retracted full-thickness tear. Tear at the greater tuberosity attachment of the supraspinatous tendon, appears as a sonolucent gap (cursors). Note the echogenic line below the tear (arrow) represents the articular cartilage edge, which is well visualized due to fluid in the above tendon tear.

Figure 10

Joint surface partial-thickness tear. The image shows the tear at the articular side of the supraspinatous tendon as a hypoechoic defect with echogenic boundary (arrows). The defect was persistent on all axial and sagital imaging planes.

Figure 11

Bursal surface partial-thickness tear. The image shows a sonolucent defect at the bursal side of the supraspinatous tendon (large arrows). Note flattening of the acromio clavicular bursa at the level of the tear (small arrow).

Figure 12

Bursal surface partial-thickness tear with bursal fluid. The image shows a large sonolucent defect in the bursal side of the supraspinatous tendon (cursors). Fluid in the subscapularis subdeltoid bursa is seen, secondary to an acute tear (arrow).

Figure 13

Intrasubstance tear. The short axis image shows central hypoechoic subscapularis tendon defect (arrow).

Figure 14

Rotator cuff tendinosis. The image reveals supraspinatous tendon degeneration as tendon widening with internal echostructure heterogeneity (arrow).

Figure 15

Rotator cuff calcifying tendonitis. Extensive foci of calcifications in the supraspinatous tendon. The image shows calcium deposition as intrasubstance hyperechoic foci with posterior acoustic shadowing (arrows) Type I calcific tendonitis.[9]

Figure 16

Subacromial tendon impingement. Split image shows the acromion (A) and supraspinatous tendon (arrow). Right plot: the shoulder is in a resting position. Left plot: the patient abducts the shoulder while the arm is in internal rotation. The supraspinatous tendon is seen bunching up lateral to the acromion.

Figure 17

Gleno-humeral joint effusion.The image shows fluid distending the glenohumeral joint capsule (long arrow). Hyperechoic posterior labrum (small arrow) adjacent to the glenoid edge (G) is separated from the humeral head (H) by synovial fluid.

Figure 18

Subacromial-subdeltoid bursal effusion. (a) Septic bursitis. The subacromial-subdeltoid bursa is distended (cursors) and filled with fluid and echogenic material (arrows), (b) Bursal hematoma. Mixed sonolucent and echogenic material filling the bursa in a patient after acromioplasty, (c) Clear bursa synovial fluid. The axial image shows sonolucent fluid in the bursa, over the bicipital tendon in the bicipital groove. Note hypoechogenicity of the biceps tendon in axial scan due to anisotropy.

Figure 19

Calcifying bursitis. (a) The image shows hyperechoic material within the subacromial subdeltoid bursa compatible with calcific deposits, most commonly calcium hydroxyapatite crystal, distension of the bursa (small arrows) by the extensive bursal calcification. Few deposits generate acoustic shadowing (large arrow), (b) Wide posterior acoustic shadow in calcific bursitis. The finding was correlated with shoulder radiography (not shown).

Figure 20

Acromio-clavicular joint pathology. (a) Acromio-clavicular joint arthropathy and subluxation. Transverse scan over the right acromio-clavicular joint shows slight widening of the joint space between the acromion (lower long arrow) and the distal end of the clavicle (upper long arrow). Increase in soft tissue width interposed between bone ends of the joint (short arrow) and associated irregularity of the articular surfaces are consistent with subluxation secondary to degenerative arthropathy. (b) Acromio-clavicular joint dislocation. Marked widening of the joint space between lateral end of the clavicle (C) and acromion (A) in a patient with chronic traumatic dislocation of the left acromioclavicular joint, confirmed by plain films (not shown).

Figure 21

Biceps brachii tendon tear. Longitudinal scan of the bicipital groove shows proximal retraction of the biceps muscle (long arrow). A fluid-filled gap with echogenic clots (small arrow) at the myotendinous junction.

Figure 22

Biceps brachii tendon synovitis. Axial scan of the biceps tendon shows fluid and synovial thickening (arrow) surrounding the biceps tendon sheath.

Figure 23

Biceps tendon subluxation. Transverse scan through the left BG shows an empty groove. Note that the groove in this patient is shallow. The biceps tendon (arrow) lies medially, anterior to the lesser tuberosity of the humerus. A small amount of fluid is seen in the tendon sheath.

Figure 24

Ultrasound-guided biopsy. (a) Echogenic soft tissue oval mass in the subcutaneous fat at the proximal arm, with multiple foci of calcification (b) Needle biopsy performed with a 16-G tru-cut needle (small arrows) under ultrasound guidance. After firing, the needle tip is seen as a strong echogenic dot (larger arrow). The patient suffered from breast carcinoma and had recently been diagnosed with papillary cystoadenocarcinoma of the ovary. Pathology revealed a metastasis from ovarian carcinoma.

Figure 25

US-guided needle aspiration of calcific deposits in the supraspinatous tendon. (a) Calcific tendonitis, (b) A 20-G spinal needle is directed into the calcific material in the tendon (arrow). Using to and fro movements of the needle, the calcium is indented by the needle. The calcifications can then be removed using needle aspiration.

Figure 26

US-guided fluid aspiration. (a) Subacromial-subdeltoid bursa synovitis in a patient with septic arthritis, (b) A 20-G spinal needle is guided into the bursa (arrow) and fluid is aspirated. Bacteriology was positive for Staphylococcus.