HERI Test: Hyperextension-Internal Rotation for Anterior Shoulder Instability

The Hyperextension-Internal Rotation (HERI) Test is an orthopedic examination technique used to assess anterior glenohumeral instability. It evaluates the integrity of the anterior capsular structures — primarily the inferior glenohumeral ligament (IGHL) — by placing the shoulder in a position that stresses the anterior restraints and measuring the resulting range of motion asymmetry between sides. The HERI Test is a relatively recent addition to the shoulder instability examination battery, with initial validation studies showing promising diagnostic utility.

Quick Reference

Full Name	Hyperextension-Internal Rotation Test
Structures Assessed	Inferior glenohumeral ligament (anterior band); anterior glenohumeral capsule
Pathology Identified	Anterior glenohumeral instability
Positive Sign	Asymmetry in hyperextension ROM greater than ~14° compared to the unaffected side
Evidence Status	Newer test; initial studies promising but large-scale validation is limited

Anatomy: Anterior Glenohumeral Stabilizers

The glenohumeral joint is inherently mobile and relies on a combination of static and dynamic structures to maintain anterior stability.

Static Stabilizers

• Inferior glenohumeral ligament (IGHL): the primary static restraint against anterior translation, particularly in positions of abduction and external rotation. The anterior band of the IGHL is the most critical structure in anterior instability. Disruption — most commonly through a Bankart lesion or capsular stretching — is the primary pathology in recurrent anterior instability.
• Middle glenohumeral ligament (MGHL): contributes to anterior stability in mid-range positions (45–60° abduction)
• Anterior labrum: deepens the glenoid socket and serves as an anchor point for the IGHL; a Bankart lesion (labral detachment at the anterior-inferior glenoid) is the classic structural finding in anterior dislocation
• Glenohumeral joint capsule: the overall capsule provides passive restraint; anterior capsular laxity or tearing contributes to instability

Dynamic Stabilizers

• Subscapularis: the primary dynamic anterior stabilizer; compresses the humeral head against the glenoid and resists anterior translation
• Rotator cuff as a whole: provides compressive joint stability through coordinated co-contraction
• Long head of the biceps: contributes to anterior stability in certain positions

Common Causes of Anterior Instability

• Traumatic dislocation: anterior dislocation — typically from a fall on an outstretched arm or forced abduction/external rotation — is the most common cause; Bankart lesion is present in the majority of cases
• Atraumatic instability: gradual capsular laxity without a discrete injury event; more common in hypermobile individuals and overhead athletes
• Hill-Sachs lesion: bony impression fracture of the posterior-superior humeral head from impaction against the glenoid during dislocation; a Hill-Sachs lesion increases recurrence risk
• Engaging Hill-Sachs lesion: a larger lesion that engages the glenoid rim in positions of abduction and external rotation, contributing to ongoing instability

How to Perform the HERI Test

Patient Position

The patient stands. The non-test arm is raised to full forward flexion (180°) and held there as a reference landmark throughout the test. This bilateral comparison is built into the test design.

Test Procedure

1. With the non-test arm held at 180° of forward flexion, position the test arm in neutral shoulder flexion with full internal rotation.
2. While maintaining full internal rotation, passively extend the test arm at the glenohumeral joint as far as possible.
3. Measure or estimate the degree of hyperextension achieved.
4. Repeat on the opposite side for direct comparison.
5. A difference of approximately 14° or greater between sides constitutes a positive test.

The non-test arm raised to full flexion serves as a visual reference and helps standardize the patient’s trunk position throughout the movement. The examiner should stabilize the scapula to minimize scapulothoracic compensation during glenohumeral extension.

Positive Sign and Interpretation

A positive HERI Test is defined as greater hyperextension range of motion on the affected side compared to the unaffected side, with an asymmetry of approximately 14° or more.

This ROM-based positive criterion distinguishes the HERI Test from most other instability tests, which rely on symptom reproduction (apprehension, pain, clunk) rather than measurable motion asymmetry. The rationale is that anterior capsular laxity or IGHL disruption allows greater glenohumeral hyperextension on the affected side before the anterior restraints engage.

Symptom reproduction during the test — apprehension, a sense of instability, or pain at the anterior joint line — adds clinical weight to a borderline ROM finding and should always be noted alongside the measurement.

Diagnostic Accuracy

The HERI Test is a newer clinical tool and its diagnostic accuracy has been evaluated in a limited number of studies. Initial research is promising, but the evidence base is not yet as robust as for more established shoulder instability tests such as the Apprehension Test or Relocation Test.

The 14° asymmetry threshold was established through initial validation work and represents the best-available cut-off for distinguishing anterior instability from normal. Clinicians should interpret HERI Test results in the context of the full clinical picture — including history, symptom pattern, and findings from other instability tests — rather than as a standalone diagnostic criterion.

As further research is published, sensitivity and specificity values may be better defined. For current evidence, refer to the primary literature cited below.

Clinical Considerations

• Use as part of an instability battery. No single test reliably diagnoses anterior shoulder instability. The HERI Test is most useful when combined with the Anterior Apprehension Test, Relocation Test, and Load and Shift Test. Concordant positive findings across multiple tests significantly increase diagnostic confidence.
• Distinguish instability from hypermobility. Generalized joint hypermobility can produce ROM asymmetry that mimics a positive HERI Test without underlying pathological instability. Assess for global hypermobility (Beighton score) and interpret ROM findings in the context of the patient’s baseline.
• Apprehension is meaningful regardless of ROM. If the patient reports apprehension or a feeling of the shoulder “giving way” during the test — even without meeting the 14° threshold — this subjective response should be weighted clinically. Apprehension during provocative testing is a consistent finding in symptomatic anterior instability.
• Consider the mechanism and history. The clinical value of any instability test increases substantially when paired with a clear history of anterior dislocation or subluxation event. A positive HERI Test in a patient with a documented first-time dislocation and young age warrants early orthopedic referral given recurrence risk.
• Imaging correlation. MRI arthrography is the preferred imaging modality for characterizing anterior labral pathology, capsular injury, and Hill-Sachs lesions when surgical management is being considered.

Related Shoulder Tests

• Full Can Test: the alternative supraspinatus assessment performed with external rotation; compare results from both positions
• Drop Arm Test: screens for full-thickness supraspinatus tear when weakness is found on the Empty Can
• Hawkins-Kennedy Test: assess for subacromial impingement contributing to pain on the Empty Can test

See all shoulder orthopedic special tests.

Frequently Asked Questions

What does a positive HERI Test indicate?

A positive HERI Test — defined as greater than ~14° of hyperextension asymmetry on the affected side — suggests anterior glenohumeral instability due to laxity or disruption of the anterior capsular structures, most commonly the inferior glenohumeral ligament. It should be interpreted alongside the full clinical picture, not in isolation.

How does the HERI Test differ from the Apprehension Test?

The Apprehension Test positions the arm in abduction and external rotation to provoke a sense of impending dislocation — it relies on symptom reproduction. The HERI Test uses a hyperextension and internal rotation position and relies primarily on measurable ROM asymmetry rather than symptoms. The two tests stress the anterior capsule through different mechanisms and are complementary rather than redundant.

Why is 14 degrees used as the positive threshold?

The 14° asymmetry threshold was established in the initial validation study for the HERI Test as the cut-off that best distinguished patients with confirmed anterior instability from controls. It reflects the degree of anterior capsular laxity detectable through ROM asymmetry. As with any threshold value, it should be interpreted alongside clinical context rather than applied as an absolute rule.

Is the HERI Test reliable enough to use clinically?

Initial studies are promising, and the test adds a ROM-based dimension to instability assessment that other tests do not provide. However, the evidence base is more limited than for established tests like the Apprehension Test. It is most appropriately used as a supplementary test within a broader instability examination rather than as the primary diagnostic tool.

Can the HERI Test be positive in the absence of instability?

Yes. Generalized joint hypermobility, previous shoulder surgery, or simply greater natural extension range of motion can produce ROM asymmetry that meets the 14° threshold without pathological instability. This is why the test must be interpreted alongside symptom response, history, and other clinical findings.

References

1. Castagna A, Nordenson U, Garofalo R, Karlsson J. Minor shoulder instability. Arthroscopy. 2007;23(2):211–215.
2. Hegedus EJ, Goode AP, Cook CE, et al. Which physical examination tests provide clinicians with the most value when examining the shoulder? Update of a systematic review with meta-analysis of individual tests. Br J Sports Med. 2012;46(14):964–978.
3. Farber AJ, Castillo R, Clough M, Bahk M, McFarland EG. Clinical assessment of three common tests for traumatic anterior shoulder instability. J Bone Joint Surg Am. 2006;88(7):1467–1474.

Video Demonstration

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