Fig. 1
Probe transverse across superior aspect of bicipital groove. Adducted arm and supinated hand (a). Biceps tendon groove (b). Schematical illustration shows how the biceps tendon (t) is located between the greater tuberosity (gt) and the lesser tuberosity (lt). Probe longitudinal to long head of biceps tendon. Adducted arm and supinated hand (c). Dynamic examination for subluxation of the tendon using internal and external rotation of the glenohumeral joint. Long head of biceps tendon (d), biceps tendon (t) and muscle tendon junction (j)
Shifting the probe superiorly and medially from the groove, with the patient’s arm in external rotation, makes it possible to evaluate the proximal intra-articular part of the LHBT. It enters the glenohumeral joint through the rotator cuff interval which is the free space between the subscapularis and supraspinatus tendons. The LHBT should be recognized between the subscapularis tendon medially and the supraspinatus tendon laterally.
Subscapularis Tendon
After LHBT examination, while maintaining the probe placed axially on the anterior aspect of the shoulder, move the probe medially until the coracoid image is visualized. The subscapularis tendon appears on the long-axis scan; it has a convex shape and a well-defined fibrillar echostructure, and it lies deep in the deltoid muscle and is superficial to the humeral head (Fig. 2a, b). To evaluate the muscular and tendon integrity, dynamic assessments during passive internal and external rotations, keeping the patient’s arm adducted, should be performed. On the short-axis scan, the multipennate structure of the normal subscapularis tendon creates a series of hypoechoic clefts (Fig. 3a, b).
Fig. 2
Probe longitudinal to the subscapularis muscle (transverse to anterior shoulder). Dynamic examination using internal and external rotation of the glenohumeral joint (a). (b) Coracoid (c); subscapularis tendon (s); coracohumeral ligament (l); deltoid muscle (d)
Fig. 3
Short-axis scan of subscapularis at level of the musculotendinous junction. The hypoechoic muscle (arrows) between the echogenic tendon slips is normal and should not be mistaken for tendinosis or tears. (a) Subscapularis tendon short axis scan tecnique; (b) Subscapularis tendon ultrasound image, humerus head (h); Subscapularis tendon (s); Muscle tissue interposed between tendon fascicles (arrows)
With the medial margin of the transducer on the coracoid process wheel and with the lateral edge of the probe upward and laterally positioned toward the acromion, the coracoacromial ligament and the anterior portion of the subacromial-subdeltoid bursa will be evaluated. From this position, the subscapularis recess and the subcoracoid bursa should be analyzed for effusion. External and internal rotations may also be used to demonstrate anteromedial impingement (the distance between coracoid process and lesser tuberosity measured in the internal rotation).
Supraspinatus Tendon
The US study starts by placing the probe on the coronal plane with its medial margin at the lateral margin of the acromion. The position of the supraspinatus tendon between the acromioclavicular arch and the humeral head makes it partially obscured by the overlying acromion process. This only makes it possible to examine its distal part in a standard neutral position (Fig. 4a, b). A better visualization of the supraspinatus tendon could be ensured using the complete internal rotation with the patient’s arm extended posteriorly, elbow flexed and pointing directly posteriorly, and with the palm of patient’s hand placed on the ipsilateral iliac wing. The long-axis and short-axis scans should be obtained. On the long-axis scan, the supraspinatus tendon is visualized as convex beak-shaped hyperechoic structure over the smooth hypoechoic band of the articular cartilage and the hyperechoic humeral cortex, ending into the great tuberosity. It lies under the layers of the subacromial subdeltoid bursa with hypoechoic fluid in it and under the hypoechoic deltoid muscle (Fig. 5a, b). On the short-axis scan, the supraspinatus tendon has a convex shape, and it consists of a homogeneous texture of medium-level echoes. A dynamic assessment is performed with passive abduction and adduction of the patient’s arm (Fig. 6a, b).
Fig. 4
(a) Probe longitudinal to supraspinatus tendon, with shoulder in neutral position. Long axis sovraspinatus tendon scan technique; (b) (SS) sovraspinatus tendon; Acromion (A); deltoid muscle (D)
Fig. 5
Probe transverse to supraspinatus tendon, with shoulder extended and internally rotated. Shoulder extension with internal rotation is required for clear visualization (a). (b) Transverse scan of supraspintus showing the echogenic rotator cable (ss). The hypoechoic subdeltoid bursa (arrow) lies between the cuff and the deltoid muscle
Fig. 6
(a) Dynamic assessment of supraspinatus can be useful in further evaluation of impingement and cuff tears. Probe over supraspinatus whilst abducting and adducting arm. Sovraspinatus tendons scan tecnique. (b) sovraspinatus tendon ultrasound image. Deltoid muscle (d); sovraspinatus tendon (ss); humerus great tuberosity (gt); subacromion deltoid bursa (arrow)
Infraspinatus and Teres Minor Tendon
The infraspinatus and teres minor tendons are evaluated using a posterior approach, with positioning of the transducer on the glenohumeral joint. The patient’s forearm is placed across his or her chest and the patient’s palm is placed on his or her opposite shoulder. The transducer is then placed over the posterior part of the glenohumeral joint, and the spine of the scapula is used as the landmark to distinguish the supraspinous fossa (transducer shifted up) from the infraspinous fossa (transducer shifted down) on the sagittal planes. The infraspinatus tendon is larger and longer than the teres minor tendon. On the long-axis scans, both of them have a fibrillar pattern. The infraspinatus tendon has a beak-shaped morphology, while the teres minor tendon appears to be a thin triangular-shaped structure. On the short-axis scans, they are visualized as convex-shaped layers with medium-level echogenicity. Dynamic assessment is performed by passive internal-external rotation, with the patient’s arm in adduction.
With posterior transverse scans of the glenohumeral joint at the level of the infraspinatus tendon, the posterior labrum-capsular complex should also be evaluated and the posterior recess of the joint should be checked for effusion during scanning. In thin subjects, the posterior labrum can be seen clearly. The transducer should be moved medially to the labrum on transverse plane to visualize the spinoglenoid notch. It is often necessary to increase the depth of the field-of-view so as not to miss this area. It is worth checking for a paralabral cyst originating in this area. The fibrocartilaginous labrum can be visualized by US as a triangular, homogeneously hyperechoic structure that caps the bony rim of the glenoid. The anterior labrum is best scanned with curved-array transducers and low frequencies (as low as 5 MHz) with an anterior or axillary transverse approach performed either with the patient’s arm in the adducted position or with the patient supine and his or her arm abducted at 90° with his or her elbow flexed (Fig. 7a, b).
Fig. 7
Sonographic scanning technique to optimize visualization of the infraspinatus and teres minor tendon; the fibers of these tendons can be stretched. This is accomplished by bringing the patient’s arm in front of the body. The arm is flexed and adducted with his or her hand resting on the contralateral shoulder. The transducer is placed on an axial plane dorsolaterally to the shoulder, just below the scapular spine and it is angled slightly inferiorly to better visualize these tendons (a). (b) Long-axis scan of infraspinatus muscle (s) as it runs toward the rotator cuff. The echogenic posterior glenoid labrum (gl) lies adjacent to the humeral head (h) and the spinoglenoid notch
Supraspinatus Full-Thickness Tears, Partial-Thickness Tears
Supraspinatus Full-Thickness Tears
Magnetic resonance (MR) and US have good diagnostic accuracy and both of these tests could be used indifferently to detect the full-thickness tears in people with shoulder pain when surgery is being considered. The diagnostic performance of MRI and US may be similar for the detection of any rotator cuff tears. However, both MRI and US may have poor sensitivity for detecting tears with moderate thickness, and the sensitivity of US in making such assessments may be much lower than that of MRI [10]. The full-thickness tears are divided into two types: (i) small to moderate sized tears and (ii) large or massive tears. The first sign of a full-thickness rotator cuff tear is a defect that extends from the joint side to the bursal side of the tendon. The space between the two heads, proximal and distal, is occupied by fluid that is anechoic or contains low-level echoes. If any doubts arise, it is always useful to make a comparative exam with the contralateral arm. Large or massive tears result in retraction of the tendon under the acromion and nonappearance of the cuff (Fig. 8). Tendon non-visualization is the single primary US finding that best predicts massive full-thickness tendon tear. Complex tears may be related: tendinosis, normal tendons with or without the presence of fluid in the subdeltoid bursa and glenohumeral joint (Fig. 9).
