Shoulder Ultrasound

An important stabilizer of the glenohumeral joint is the rotator cuff formed by the subscapular tendon anteriorly, the supraspinatus tendon superiorly and the infraspinatus and teres minor tendon posteriorly.
Of these latter two tendons, only the infraspinatus tendon is partly shown in this illustration.
The rotator cuff interval is the gap in the rotator cuff between the subscapular and supraspinatus tendon.
Here the humeral head is not covered by the rotator cuff, but by the intra-articular portion of the long head of the biceps tendon, which is covered by the coracohumeral ligament.
The normal anatomy is also discussed here.

This is a posterior view of the shoulder demonstrating the  supraspinatus, infraspinatus and teres minor muscle and tendon.

Rotator cuff interval

The rotator cuff interval is the area where the humeral head is not covered by the rotator cuff.
It is located between the anterior edge of the supraspinatus tendon and the superior edge of the subscapularis tendon.
When you are looking for supraspinatus tears, it is important to examine the attachment of the tendon to the greater tuberosity from posterior to the border of the rotator cuff interval, as many tears (so called rim rent tears) are located in this anterior part.

The biceps tendon is stabilized by a capsuloligamentous complex, which is called the biceps pulley.
It is composed of the superior glenohumeral ligament, the coracohumeral ligament and the distal attachment of the subscapularis tendon (figure).

Spinoglenoid notch

The spinoglenoid notch is the area located between the lateral base of the scapular spine and the glenoid process of the scapula.
It connects the supraspinatus fossa with the infraspinatus fossa and allows passage for the suprascapular nerve and artery.
In this area ganglion cysts can arise compressing the nerve resulting in shoulder pain and infraspinatus atrophy.
These cysts are caused by tears in the posterosuperior glenoid labrum.

A high-resolution linear probe (≥10 MHZ) is used.
In addition sometimes a curvilinear probe (3.5 MHZ) is used to examine the glenohumeral joint as a whole.

The usual order of examination is first to look at the tendon of the long head of the biceps to look for effuson, a tear or subluxation of the tendon.
Sometimes fatty atrophy can be seen of the muscle or at the myotendinous junction.
Then study the tendons of the subscapular, supra- and infraspinatus muscle and especially look for tears.

You can expand the examination with a study of the AC-joint, spinoglenoid notch, posterior labrum and glenohumeral joint.

Long head of the biceps tendon

The long head of biceps (LHB) is easily appreciated by placing the probe on the muscle belly in the arm and moving upwards to examine the myotendinous junction and the tendon.

The forearm of the patient is supinated and in slight internal rotation towards the contralateral knee.
The LHB is seen as a rounded structure with a fibrillary pattern (black arrow) within the intertubercular groove (white arrowheads).

Video of the examination of the long head of the biceps in the transverse plane.

Click in the left upper corner for a full screen view.

Anisotropy
When the direction of the ultrasound beam is not perpendicular to the LHB, you will get less reflection of sound waves.
This can result in anisotropy.
This artifact refers to a darkening and loss of resolution of the structure, that you are examining (black arrow).
You may even get the impression, that the LHB is not within the groove and maybe dislocated.
By repositioning the transducer to perpendicular the normal echogenic LHB will appear (white arrow).
Notice that in this image the subscapular tendon also appears anechoic due to this effect.

Rotator cuff interval

When the patient brings the elbow slightly backward, while the forearm is still supinated, you get a better view on the intra-articular part of the biceps tendon in the rotator cuff interval.
This position is called the Jugger’s position (figure).

Image
Transverse view of the rotator cuff interval.
The greater tubercle, the lesser tuberosity, the LHB (arrow), the coracohumeral ligament (arrowheads), which covers the LHB.  

Is deze opname beter, omdat het interval op de humerus kop gelegen is. Je zou de tuberkels niet in beeld moeten hebben.

Image
Transverse view of the rotator cuff interval.
The LHB (arrow) is seen lying over the smooth humeral head.
the coracohumeral ligament (arrowheads), which covers the LHB.  

Subscapular tendon

The arm is placed beside the trunk with an angle of 90º between the arm and forearm.
The forearm is in supination and external rotation.
The probe is brought medially to examine the SSC tendon passing underneath the coracoid process.

Video of normal subscapular movement
During internal and external rotation of the forearm, the whole tendon should be seen sliding under the coracoid (see video).
Impingement is noted when there is incomplete or delayed passage of the tendon (see chapter on impingement).

Click in the left upper corner for a full screen view.

Supraspinatus tendon

The good position for the supraspinatus examination is the modified Crass position.
To obtain this position, the patient is asked to place the hand on the ipsilateral hip or towards their back pocket (Fig).
An alternative is the Crass position by placing the patient’s arm in endorotation behind the shoulder.

Infraspinatus tendon

Examining the infraspinatus tendon may be a bit challenging, as it is difficult to differentiate the infraspinatus from the supraspinatus.
The best position to appreciate the infraspinatus tendon is by placing the hand on the contralateral shoulder.
Place the probe in the same position for examining the supraspinatus.
Once you get the supraspinatus in view, bring the probe in a downward direction.
There will be a subtle minor gap, then you will notice the smaller outline of the infraspinatus tendon.

Video of the infraspinatus tendon.

Click in the left upper corner for a full screen view.

Acromioclavicular joint

The acromioclavicular joint is easily appreciated by palpating the bony projection and then placing the probe over it.
A normal acromioclavicular joint shows a smooth contour of the bony articular surfaces.

Spinoglenoid notch

The spinoglenoid notch is the area located between the lateral base of the scapular spine and the glenoid process of the scapula.
It connects the supraspinatus fossa with the infraspinatus fossa and allows passage for the suprascapular nerve and artery.
Cysts in this area are often ganglion cysts and can compress the nerve resulting in shoulder pain and infraspinatus atrophy.
These cysts arise from underlying joint or tendon pathology and are asociated with labral tears of the glenohumeral joint.

It is examined by palpating the blade of the scapula on the back of the shoulder before the origin of the acromion process, then placing the probe over it.
It is beneficial to angulate the probe to take the same orientation as the notch.

The suprascapular nerve appears as a collection of echogenic bundles due to the fascicular pattern (figure).
The suprascapular vessels appear as anechoic structures (Fig. 20).
Power Doppler can be beneficial to trace the suprascapular vessels in order to find the nerve (arrow).

Posterior labrum and glenohumeral joint

The posterior labrum can be examined by placing the probe at the posterior aspect of the glenohumeral articulation.
The labrum is seen as a triangular echogenic structure, which is more echogenic than the adjacent anechoic cartilage (arrow).

Biceps tendinopathy

Images
Two examples of a thickened long head of the biceps tendon.
Notice the irregular echo-pattern especially on the image on the right.
There is hypervascularity and some surrounding fluid (arrows).

Tear of the long head of the biceps (LHB)
The most common site of LHB injury is the myotendinous junction and the adjacent part of the tendon.
The LHB tears are easily appreciated as anechoic fluid interrupting the muscle fibres.
The echogenicity varies with the age of the injury.
Acute tears are usually anechoic, while chronic tears may show reflective echoes within the fluid.

Images
Two examples of tears at the myotendinous junction of the LHB.
The tear is completely anechoic suggesting an acute tear.   

Biceps (sub)luxation
The LHB tendon should be centralized within the bicipital groove.
Eccentric location denotes laxity or rupture of the biceps pulley.

Rotator cuff tears

Partial thickness tears involve only a part of the tendon and do not involve the full thickness.
It can be located on the articular or on the bursal side (figure).
An intrasubstance tear is also a partial thickness tear.

Full thickness tears can be complete or may involve only a part of a tendon.
This is called an incomplete full-thickness tear and is just like a hole in a tendon (figure).

Full thickness tears

This image shows a complete full thickness tear of the supraspinatus tendon.
There is a small hypoechoic fluid collection.
Both tendon edges are blunt and retracted (arrowheads).

Here another example of a ful thickness tears of the supraspinatus tendon.
The gap is filled with some fluid from the glenohumeral joint (arrow)

Partial thickness tears

Here two examples of a partial tear on the articular side.

Intrasubstance tears

Intrasubstance tears are partial tears that do not extend to the articular or bursal surface of the tendon.
The images show two examples of a small intrasubstance tear.

Impingement

During endorotation a normal subscapular tendon should show almost complete passage underneath the coracoid process.
Impingement is suspected when a residual portion of the tendon is still visible during maximum endorotation.

Images
During endorotation there is incomplete passage under the coracoid and buckling of the subscapular tendon.

Video of subscapular impingement.
Click in the left upper corner for a full screen view.

Supraspinatus impingement
This is usually a result of acromion pathology and chronic muscle insult.
Impingement can be suspected when there is a residual portion of the tendon, that does not slide under the acromion during maximum abduction.

Tendinosis

The term tendinosis is used rather than tendinitis because there is no active inflammation, but instead it is a degenerative process with mucoid degeneration.
The tendon is frequently thickened and may show hypoechoic striated areas.

Images

Calcific tendinopathy

Calcific tendinopathy develops when calcium deposits build up in the tendons.
It most commonly affects the tendons of the rotator cuff of the shoulder.
These deposits can become inflamed and cause pain.

Images

1. Markedly thickened supraspinatus tendon with chunky calcifications casting extensive posterior shadow.
2. Small calcification in the supraspinatus tendon.

Bursitis

Normally the bursal space is collapsed and barely distinguishable by ultrasound (arrows)    

Acute bursitis appears sonographically as distension of the bursa (yellow arrow).
Chronic bursitis may show a thick wall (white arrow).   

AC pathology

Osteoarthrosis
Recognizing symptomatic osteoarthrosis of the AC joint is challenging, as the radiographic and ultrasound findings of joint degeneration are ubiquitous in adults and correlate poorly with symptoms. 

Images
Osteoarthrosis of the AC joint with cortical irregularity and bulging of the capsule.   

AC-arthritis
This image is of  a 19-year-old male athlete who sustained an injury during a wrestling match.
There were no signs of septic arthritis and he was diagnosed with post-traumatic arthritis.
He improved with anti-inflammatory medication and rest.