2 The Shoulder: Diagnostic Imaging

10.1055/b-0038-160897

2 The Shoulder: Diagnostic Imaging

Abstract

Ultrasound of the shoulder is one of the most common applications of musculoskeletal ultrasound both as a diagnostic tool and as an aid to accurate intervention. This chapter outlines the correct positioning of both patient and probe to ensure accurate visualization of the key structures around the shoulder. Of particular importance when examining the shoulder is the need to assess holistically given the interplay between structures, for example, the relevance of fluid within the subacromial bursa and bicipital sheath in a full thickness rotator cuff tear. A high-frequency (7-15 MHz) linear probe with a relatively large footprint should be used for diagnostic imaging to allow sufficient anatomical resolution.

2.1 Diagnostic Imaging of the Shoulder: Introduction

The shoulder joint should be considered as a whole, given the interplay between the tendons of the rotator cuff, the bursae, the tendon of the long head of biceps and the acromioclavicular joint. In particular, ultrasound of the shoulder should include dynamic scanning of structures to assess for impingement syndromes.

Imaging includes the following:

Long head of biceps tendon.
Subscapularis tendon.
Dynamic assessment for long head of biceps subluxation and subcoracoid/anterior impingement.
Supraspinatus tendon and subacromial bursa.
Infraspinatus tendon and posterior glenohumeral joint.
Suprascapular notch and suprascapular nerve.
Acromioclavicular joint.
Sternoclavicular joint.

2.1.1 Long Head of Biceps Tendon

Transverse Scan

The patient is seated with the elbow flexed to 90 degrees and the arm supported on a pillow. The arm may be placed in slight internal rotation. The probe is placed in the anatomical transverse plane so that it is positioned transversely over the long biceps tendon found in the bicipital groove between the greater and lesser tuberosities. Scan proximally as far as possible before the tendon passes form view below the acromion and distally to the musculotendinous junction at the level of the pectoralis major tendon (Fig. 2‑1 , Fig. 2‑2 , Fig. 2‑3 , Fig. 2‑4 , Fig. 2‑5 ).

Fig. 2.2 Transverse image of long head of biceps in bicipital groove. AD, anterior deltoid; GT, greater tuberosity; LT, lesser tuberosity.

Fig. 2.3 Transverse image of long head of biceps proximal to the bicipital groove. Note the tendon is oval in appearance as it turns medially to run over the humeral head. HH, humeral head; SST, supraspinatus tendon; SUB, subscapularis tendon.

Fig. 2.4 Transverse image of the long head of biceps (*yellow arrow*) distal to the bicipital groove at the level of the pectoralis major tendon.

Fig. 2.5 Anterior coronal view of the right glenohumeral and acromioclavicular joints. The subacromial bursa is the synovial cavity located just below the acromion, which communicates with the subdeltoid bursa in most individuals, forming the so-called subacromial–subdeltoid bursa (SSB). The SSB is located deep to the deltoid muscle and the coracoacromial arch and extends laterally beyond the humeral attachment of the rotator cuff anteriorly over the intertubercular groove, medially to the acromioclavicular joint, and posteriorly over the rotator cuff. It is important when scanning this region to follow the bursa to its most inferior margin as this is often where fluid is seen. The bicipital sheath may be seen to extend some way inferiorly below the greater and lesser tuberosities. Scanning should include this region to ensure that any fluid distension of the bicipital sheath is not missed. (Reproduced from Schuenke, Schulte, and Schumacher, Atlas of Anatomy, 2nd edition, ©2014, Thieme Publishers, New York. Illustration by Karl Wesker/Markus Voll.)

The subacromial–subdeltoid bursa (SSB) is located deep to the deltoid muscle and the coracoacromial arch and extends laterally beyond the humeral attachment of the rotator cuff anteriorly over the intertubercular groove, medially to the acromioclavicular joint, and posteriorly over the rotator cuff. It is important when scanning this region to follow the bursa to its most inferior margin as this is often where fluid is seen.

The bicipital sheath may be seen to extend some way inferiorly below the greater and lesser tuberosities. Scanning should include this region to ensure that any fluid distension of the bicipital sheath is not missed.

Longitudinal Scan

The probe is returned to the level of the bicipital groove and turned through 90 degrees so that it is positioned in the anatomical sagittal plane to view the tendon longitudinally (Fig. 2‑6 , Fig. 2‑7 ).

Fig. 2.7 Longitudinal image of the long head of biceps in the bicipital groove. The tendon appears as a fibrillar band (*yellow arrows*) below the anterior deltoid (AD) muscle.

The Long Head of Biceps: Pathology

See Fig. 2‑8 , Fig. 2‑9 , Fig. 2‑10 ; Fig. 2‑11 a,b; Fig. 2‑12 a,b; Fig. 2‑13 a,b.

Fig. 2.8 Transverse image of the long head biceps (*yellow arrow*). The image demonstrates fluid around the tendon within the bicipital sheath (*white arrowheads*). The fluid extends both medially and laterally around the tendon due to the pressure of the probe. A longitudinal scan over the tendon would not have demonstrated any fluid. AD, anterior deltoid.

Fig. 2.9 Longitudinal view of the bicipital groove. The image fails to demonstrate the normal linear fibrillar pattern of the tendon in keeping with a tendon rupture. Instead the bicipital groove appears filled with echogenic material (*dashed yellow arrows*). AD, anterior deltoid; yellow arrow dashed, bicipital groove demonstrating no clear long head of biceps tendon.

Fig. 2.10 Longitudinal image of the long head of biceps tendon (*yellow arrows*). The tendon appears intact with a good fibrillar pattern. However, fluid and some synovial thickening are noted surrounding the tendon within the bicipital groove (*yellow dashed arrow*).

Fig. 2.11 (a) Transverse image of the long head of biceps at the level of the bicipital groove. The image demonstrates the long head biceps (*yellow arrow*) as being subluxed medially and overlying the subscapularis tendon (*white arrowhead*). The bicipital groove appears empty (*curved yellow arrow*). (b) Longitudinal image confirms that the long head biceps is intact (*yellow arrows*) but subluxed medially and is overlying the subscapularis tendon (*white arrowhead*).

Fig. 2.12 (**a, b**) Transverse image of the bicipital groove. The image demonstrates a tendinopathic long head of biceps (*yellow arrow*). In addition, there is synovial thickening within the bicipital sheath (*white star*) with bowing of the transverse ligament (*white curved arrow*). The right hand image demonstrates the associated Doppler signal within the bicipital sheath indicating tenosynovitis.

Fig. 2.13 (a) Transverse images of the long head of biceps. The image above demonstrates a tendinopathic tendon (*yellow arrow*) at the level of the bicipital groove with bowing of the transverse ligament (*white curved arrow*) and synovial thickening (*white stars*). Doppler imaging also demonstrates an associated synovitis. (b) This image is taken distally to the bicipital groove and demonstrates fluid within the sheath (*dashed yellow arrow*).

2.1.2 Subscapularis Tendon

Longitudinal Scan

The patient is seated with the elbow flexed to 90 degrees and the arm supported on a pillow. The arm should be placed in slight external rotation. The long head of the biceps may be used as a landmark. The probe is placed in the anatomical transverse plane to image the subscapularis tendon longitudinally. The arm should be externally and internally rotated to view the greatest extent of the tendon possible and to assess for anterior impingement (Fig. 2‑14 , Fig. 2‑15 ).