Shoulder ultrasound is a first-line exam for extra-articular pain around the glenohumeral joint. When the study is complete and the beam stays perpendicular to tendon fibers, ultrasound for shoulder evaluation can confirm or exclude rotator cuff tears, biceps tendon disease, bursitis, calcific tendinopathy, and acromioclavicular arthropathy, and it adds dynamic information that static MRI cannot. This scanner-side guide covers positioning, standard rotator cuff and biceps views, normal anatomy, and pitfalls that cause false-positive or false-negative reads.
What an Ultrasound of the Shoulder Shows
A diagnostic ultrasound of the shoulder interrogates extra-articular soft tissue. It does not replace MRI for labral tears, cartilage, marrow, or deep capsuloligamentous injury. It is the right first test when the question is cuff integrity, biceps stability, bursal disease, or a sonographically accessible mass. Address these items in every report:
- Long head of biceps: tendinopathy, tenosynovitis, split, rupture, subluxation, or dislocation
- Subscapularis, supraspinatus, infraspinatus, and teres minor: tendinosis, partial- or full-thickness tear, and muscle atrophy
- Subacromial-subdeltoid bursa, calcification, and tuberosity cortex
- Acromioclavicular joint, posterior recess, and spinoglenoid notch
- Rotator interval appearance when adhesive capsulitis is in the differential
Positioning, Transducer, and Setup
Seat the patient on a rotating stool with the arm uncovered and free to rotate and abduct. Use a high-frequency linear transducer. In a large or postoperative shoulder, lower the frequency or switch to a compact curvilinear transducer so the cuff is not under-penetrated. Keep a consistent laterality routine and state in the report which side was examined. Contralateral images help when anatomy is variant or postsurgical.
Shoulder Ultrasound Protocol: Standard Views
Use a fixed sequence so no tendon is omitted. Document each structure in short and long axis, and store cine clips of dynamic maneuvers when they change the interpretation. A complete diagnostic protocol is more extensive than a focused point-of-care ultrasound exam. Purpose-driven scope is discussed further in IAME's diagnostic versus point-of-care ultrasound webinar.
Long Head of the Biceps Tendon
Rest the arm at the side with the elbow flexed and the forearm supinated. Start short axis over the bicipital groove, then rotate into long axis. The normal tendon is oval and fibrillar. A thin fluid rim can be physiologic. An empty groove requires a search for medial dislocation under subscapularis or for distal retraction. Medial subluxation often accompanies a superior subscapularis tear. Dynamic external rotation confirms that the tendon stays seated.
Subscapularis
Externally rotate the arm to clear the lesser tuberosity from under the coracoid. Scan transversely across the lesser tuberosity, then along the tendon long axis. Multipennate clefts between fiber bundles are normal and should not be called tears. Inspect the superior insertion most carefully, and always correlate biceps subluxation with subscapularis integrity.
Supraspinatus and Rotator Interval
Place the hand behind the back or on the ipsilateral hip (Crass or modified Crass) so the footprint lies anterior to the acromion. Align the transducer with the tendon long axis, then turn 90 degrees for short axis. Cover the full footprint from the biceps and rotator interval anteriorly to infraspinatus posteriorly. On long axis the tendon should taper to a sharp greater tuberosity insertion. On short axis it should form a uniform convex band. The rotator interval is relatively hypoechoic. Do not report that interval as an anterior tear.
Infraspinatus, Teres Minor, and Posterior Recess
Have the patient place the hand on the opposite shoulder. Scan below the scapular spine along infraspinatus, then inferiorly for teres minor, in both axes. Compare muscle bulk and echotexture with the other side when atrophy is a concern. The posterior recess is a sensitive site for joint effusion. Trace the spinoglenoid notch for paralabral cysts that may affect the suprascapular nerve.
Acromioclavicular Joint, Bursa, and Dynamic Testing
Scan the AC joint in the coronal plane for capsular bulging, cortical irregularity, and ganglia. The subacromial-subdeltoid bursa is a thin line deep to deltoid. Compressible fluid or synovial thickening is abnormal. Dynamic abduction may show bursal bunching. Treat that finding as supportive of the clinical exam rather than a stand-alone diagnosis of impingement.
Tears, Bursitis, and Adhesive Capsulitis
A full-thickness tear is a gap from the articular to the bursal surface, often filled with fluid or bursal tissue, with or without retraction. Cortical irregularity of the greater tuberosity supports the diagnosis. Measure the defect in two planes (anteroposterior extent on short axis and retraction on long axis) and name every tendon involved.
Partial-thickness tears are articular-sided, bursal-sided, or interstitial. State location, approximate depth relative to tendon thickness, and AP extent. Tendinosis is thickening with hypoechoic, disordered fibrils and no discrete cleft. Calcific tendinopathy appears as echogenic foci, with or without shadowing, most often in supraspinatus.
Adhesive capsulitis is a clinical diagnosis. Frozen shoulder ultrasound may show limited external rotation, a thickened coracohumeral ligament or rotator interval, and interval hyperemia with an intact cuff. Those signs overlap with rotator interval tendinopathy and need range-of-motion correlation. Reports should distinguish partial from full thickness, give two-plane size, and comment on biceps stability, bursa, AC joint, and muscle quality.
Pitfalls That Cause False Reads
Most overcalled or missed tears are technical. Build these checks into every exam.
Keep the transducer perpendicular to the tendon. Hypoechoic fibrils that brighten with heel-toe angulation are not a tear.
- Anisotropy. Off-perpendicular fibrils look hypoechoic and mimic a tear. Heel-toe until the tendon brightens before calling a defect.
- Incomplete footprint coverage. The anterior supraspinatus leading edge and superior subscapularis are the segments most often skipped.
- Rotator interval and cable. The interval is normally less echogenic. The cable can resemble a residual band or focal thickening.
- Multipennate subscapularis and the posterior bare area. Both are normal and can mimic articular-sided tearing.
- Bursal fluid without a documented gap. Combined bursal and glenohumeral fluid should prompt a search for a full-thickness communication. Bursal fluid alone is nonspecific.
- Postoperative irregularity and pseudotendon. Residual thickening is not a recurrent tear. Thin bursal scar can simulate an intact cuff if you do not follow tendon to muscle.
Confirm before leaving the room:
- Biceps in two planes with dynamic external rotation
- Subscapularis in external rotation
- Full supraspinatus footprint in both axes
- Infraspinatus and teres minor, including muscle bulk
- Posterior recess and spinoglenoid notch
- Acromioclavicular joint and bursa
- Dynamic abduction if indicated
A complete, two-axis exam of each tendon remains more important than any single sign. Measure tears in two planes, and interpret dynamic findings with the clinical exam. Worked examples of intact, partial-thickness, and full-thickness patterns are reviewed in IAME's Ultrasound of the Shoulder Case Series. IAME offers accredited ultrasound CME courses on shoulder and musculoskeletal scanning for clinicians who want structured review of protocol and pathology.
Frequently Asked Questions
What does an ultrasound of the shoulder show?
It shows the rotator cuff, long head of biceps, bursa, tuberosity cortex, and acromioclavicular joint, and it can test those structures dynamically. It does not reliably show the labrum, articular cartilage, or marrow, which are MRI questions.
How long does it take to get ultrasound results?
Scanning often takes about 10 to 20 minutes. If the operator interprets at the bedside, results can be immediate. If a sonographer scans and a radiologist interprets, turnaround follows that practice's usual reporting workflow. Check local process rather than a single rule.
What is the difference between ultrasound and USG?
USG means ultrasonography and is the same test as diagnostic ultrasound. Orders may say ultrasound, US, or USG. For the shoulder, the relevant issue is whether a complete protocol was performed by an experienced operator, not the abbreviation on the request.
At what age does shoulder pain typically peak?
No single age applies to every diagnosis. Degenerative cuff disease and adhesive capsulitis are more common in middle-aged and older adults. Instability is seen more often in younger patients. Age should shape the differential, not replace history, exam, and protocolled imaging.
