Ultrasound examination can be very useful in diagnosing both rotator cuff and non-rotator cuff disorders of the shoulder.
The rotator cuff consists of the tendons of four muscles: Subscapularis muscle that originates from the subscapular fossa and inserts into the humeral lesser tuberosity.
Supraspinatus muscle is localized in supraspinous fossa,
and laterally inserts into the greater tuberosity of the humerus.
Infraspinatus muscle takes origin from the infraspinous fossa,
and teres minor muscle originates just inferiorly.
They both insert into the greater tuberosity.
Normal ultrasound anatomy of supraspinatus tendon and surrounding shoulder structures is shown and explained on figures 1,
2 and 3.
Fig. 1: Normal supraspinatus tendon, longitudinal view
Fig. 2: Supraspinatus tendon, normal anatomy, longitudinal view
Fig. 3: Supraspinatus tendon, transverse view
Ultrasound evaluation has similar accuracy as MRI in detecting rotator cuff tears.
The tears of the rotator cuff can be total,
or subtotal affecting articular or bursal side of the tendon.
Direct ultrasound signs of rotator cuff tear are hypoechoic or anechoic defects of the bursal or articular side of the tendon for partial thickness tears.
Absence of a part of the tendon ,
replaced by fluid is characteristic for full thickness tendon tear.
Various degree of tendon retraction can also be observed.
There are also indirect signs such as greater tuberosity irregularity,
or increased amount of fluid in subacromion subdeltoid bursa.
On fig.
4 a bursal-side partial thickness tear of supraspinatus tendon,
with increased amount of subacromion subdeltoid bursal fluid is shown.
Tendon of supraspinatus is thickened with irregularity of great portion of the fibres.
Fig. 4: Supraspinatus tendon-bursal side partial thickness tear
Full thickness tear with retraction of the supraspinatus tendon (chronic) is observed of fig.
5.
There is also an irregularity of the greater tuberosity.
Fig. 5: Supraspinatus tendon-full thickness chronic tear
Other conditions affecting the supraspinatus tendon can be also adequately proven using ultrasound.
The most common disorders are degenerative tendinosis,
calcifying tendonitis,
bursitis,
shoulder impingement syndrome.
Degenerative changes-tendinosis of supraspinatus tendon are shown on fig.
6.
The tendon is thickened,
irregular,
heteroechoic,
but there are no signs of tendon tear.
Fig. 6: Supraspinatus tendon tendinosis
Calcifying tendonitis is a frequent generator of shoulder pain.
Ultrasound has a high sensitivity in detecting tendon calcifications.
They appear as variously hiperechoic structures with different size,
sometimes very big,
and posterior shadowing.
Supraspinatus is the most affected of the rotator cuff tendons.
Cases of advanced supraspinatus calcifying tendonitis are shown in fig.
7 and 8.
Fig. 7: Supraspinatus tendon calcifying tendonitis
Fig. 8: Supraspinatus tendon calcifying tendonitis-transverse view
Subacromial subdeltoid bursitis is evident on fig.
9.
Supraspinatus tendon is heterogeneous,
and increased amount of anechoic fluid in the bursa is visualized.
Fig. 9: Subacromial subdeltoid bursitis
Normal anatomy of subscapularis tendon is demonstrated on fig 10 and 11.
Subscapularis tendon tear is less common and is usually combined with the tear of supraspinatus tendon.
Fig. 10: Normal Subscapularis tendon-longitudinal view
Fig. 11: Normal subscapularis tendon-transverse view
Subdeltoid bursitis with a huge amount of fluid over subscapularis tendon is evident on fig.12.
Fig. 12: Subdeltoid bursitis
Ultrasound image of normal infraspinatus tendon is demonstrated on fig 13.
Fig. 13: Normal Infraspinatus tendon-longitudinal view
Non rotator cuff disorders affect the shoulder in many cases,
and can be adequately evaluated with ultrasound.
Superiorly of the myotendinous junction,
the tendon of the long head of biceps brachii enters the bicipital groove.
More cranially it passes into the rotator interval (the space between the supraspinatus and subscapularis tendon.
Then the tendon extends to the upper pole of the humeral head and inserts on the superior rim of the glenoid.
Normal ultrasound appearance of tendon of the long head of biceps in the bicipital groove is exposed on fig.
14 and 15.
Fig. 14: Tendon of long head of biceps brachii-longitudinal view
Fig. 15: Tendon of long head of biceps brachii in the bicipital groove-transverse view
Various traumatic and degenerative conditions can affect the tendon.
Among the most common are medial dislocation/subluxation of the tendon and tendon degeneration-tendinosis.
Acute or chronic tendon tear occurs less often.
Tendinosis of the long head of biceps tendon is visualized on image 16.
The tendon is hypoechoic,
with increased diameter,
and hypoechoic fluid around it is visible (in the tendon sheath).
Fig. 16: Degeneration of the tendon of long head of biceps brachii-transverse view
Abnormalities of other parts of the shoulder: acromioclavicular joint traumatic and degenerative lesions,
bony abnormalities (compression fractures,
avulsions of the tuberosities),
cysts,
joint effusion,
synovial disorders can also be diagnosed with ultrasound examination.
Ultrasound image of normal acromioclavicular joint is shown on fig.
17.
Fig. 17: Acromioclavicular joint
Arthritis of the acromioclavicular joint.
Heterogeneous joint space is visible on fig.
18.
Fig. 18: Acromioclavicular joint osteoarthritis