Shoulder Orthopaedic Test: Inferior Sulcus Test

The Inferior Sulcus Test, also called the Sulcus Sign, assesses inferior glenohumeral translation by applying a downward traction force to the relaxed arm and observing for a visible or palpable sulcus below the acromion. It is commonly used to support assessment reasoning around inferior shoulder laxity and multidirectional instability.

A positive finding may include a visible sulcus, increased inferior translation, apprehension or familiar instability symptoms. However, laxity is not the same as symptomatic instability. Some asymptomatic people demonstrate inferior laxity, so the result must be interpreted with history, symptoms, apprehension, functional instability reports and other shoulder tests.

Introduction

The Inferior Sulcus Test is a shoulder special test used to assess inferior translation of the humeral head. When downward traction is applied to the arm, a visible dimple or gap may appear below the acromion. This is called the sulcus sign.

The test is commonly associated with inferior glenohumeral laxity and multidirectional instability. However, inferior laxity can be present in people without symptoms. This makes interpretation important: a sulcus sign alone does not confirm a clinically significant instability problem.

The test is most useful when the visible sulcus is associated with apprehension, familiar symptoms, functional instability reports, a history of subluxation or dislocation, or positive findings on other instability tests.

For Measurz, the key is to record the size of the sulcus, side tested, arm position, pain or apprehension, symptom familiarity, comparison side and whether the finding appears symptomatic or incidental.

Quick Summary

Test name: Inferior Sulcus Test / Sulcus Sign
Region: Shoulder / glenohumeral joint
Primary purpose: Assess inferior glenohumeral translation and shoulder laxity
Commonly associated presentation: Inferior laxity, multidirectional instability, symptomatic shoulder instability
Positive finding: Visible sulcus below the acromion, increased inferior translation, apprehension or familiar instability symptoms
Negative finding: No visible sulcus, no apprehension and no meaningful side-to-side difference
Main limitation: Laxity may be present without symptoms; the test does not confirm instability on its own.

What Is the Inferior Sulcus Test?

The Inferior Sulcus Test is a shoulder laxity test.

The client sits or stands with the arm relaxed by the side. The professional applies a downward traction force to the humerus. A positive sulcus sign is observed when a visible indentation appears below the acromion as the humeral head translates inferiorly.

The sulcus may be graded by the amount of inferior displacement, commonly using:

• Grade 0: no visible sulcus
• Grade 1: less than 1 cm
• Grade 2: 1–2 cm
• Grade 3: more than 2 cm

Grading should be interpreted carefully because laxity can be normal for some people.

Why It Is Used

The Inferior Sulcus Test may be used to support assessment reasoning around:

• Inferior glenohumeral laxity
• Multidirectional shoulder instability
• Generalised shoulder laxity
• History of shoulder subluxation or dislocation
• Apprehension or instability symptoms
• Shoulder symptoms in overhead athletes
• Shoulder instability after trauma
• Side-to-side laxity comparison
• Baseline and retest documentation in Measurz

It is most useful when the test reproduces familiar symptoms or is part of a broader instability pattern.

What It Assesses

The Inferior Sulcus Test assesses inferior translation of the humeral head relative to the glenoid.

It may provide information about:

• Inferior shoulder laxity
• Sulcus size
• Side-to-side difference
• Apprehension
• Symptom reproduction
• Possible multidirectional instability pattern
• Shoulder capsule laxity
• Instability-type assessment reasoning

It does not directly assess:

• Symptomatic instability with certainty
• Labral integrity
• Capsular lesion with certainty
• Rotator cuff integrity
• Imaging findings
• Shoulder strength
• Scapular control
• Readiness for sport or work
• Treatment need

Who It Is Useful For

The Inferior Sulcus Test may be useful for clients with:

• Shoulder instability symptoms
• Recurrent subluxation sensations
• Multidirectional instability-type presentation
• A feeling that the shoulder slips or drops
• Overhead sport symptoms
• Generalised joint laxity
• Shoulder apprehension
• A history of dislocation or subluxation
• A need for baseline and retest documentation

It may also be useful for professionals learning the difference between laxity and symptomatic instability.

When to Use This Test

Consider using the Inferior Sulcus Test when:

• Shoulder instability is part of the assessment reasoning
• The client reports slipping, subluxation or giving way
• Multidirectional instability is being considered
• You want to compare inferior laxity side to side
• Apprehension is relevant
• You are building a broader shoulder instability profile

It should be combined with apprehension, relocation, load-and-shift, Gagey or other instability tests where appropriate and within scope.

When Not to Use or When to Be Cautious

Use caution or avoid the test when:

• Recent acute dislocation or major trauma is suspected
• Fracture is possible
• The shoulder is highly irritable
• The client is apprehensive before testing
• There is severe pain before testing
• Neurological symptoms are present
• The professional cannot safely support the arm
• The test would not change assessment reasoning

Stop if pain increases sharply, apprehension becomes high, neurological symptoms occur, the client feels the shoulder is slipping, or the client asks to stop.

Equipment Required

The Inferior Sulcus Test usually requires no equipment.

Optional equipment includes:

• Measurz app
• Pain rating scale
• Notes field for sulcus grade and apprehension
• Shoulder instability test records
• Video or image record only where appropriate
• Generalised joint laxity screening where relevant

Step-by-Step Protocol / Practice

Setup

Ask the client to sit or stand comfortably with the tested arm relaxed by the side.

Explain the test:

“I am going to gently apply downward pressure through your arm and observe whether the top of the shoulder shows increased movement. Tell me if this feels painful, unstable or familiar.”

Test the less symptomatic side first where appropriate.

Client position

The client sits or stands with:

• Trunk upright
• Shoulder relaxed
• Arm by the side
• Elbow relaxed
• Forearm relaxed
• No active shoulder shrugging or bracing

Examiner/professional position

The professional stands beside or slightly behind the tested shoulder.

The professional should be able to observe the space below the acromion while applying a controlled downward force.

Hand placement

Hold the client’s distal humerus, elbow, forearm or wrist depending on comfort and control.

Apply traction downward through the arm.

Avoid gripping painfully.

Stabilisation

The shoulder girdle should remain relaxed.

Do not forcefully depress the scapula unless using a specific modified variation and recording it clearly.

Movement or force direction

Apply an inferior traction force to the humerus.

The force should be:

• Gradual
• Controlled
• Symptom-limited
• Compared with the other side where appropriate

Observe for a sulcus below the acromion.

Instructions

Tell the client:

“Stay relaxed. Let me know if this causes pain, apprehension, slipping, or your familiar shoulder symptoms.”

Positive finding

A positive finding may include:

• Visible sulcus below the acromion
• Increased inferior translation compared with the other side
• Sulcus greater than expected
• Apprehension
• Familiar instability symptoms
• Feeling of slipping or dropping
• Symptoms that match the client’s history

Record sulcus size and symptom response separately.

Negative finding

A negative finding may include:

• No visible sulcus
• No meaningful inferior translation
• No apprehension
• No familiar symptoms
• Similar response to the opposite side

A negative result does not fully exclude shoulder instability.

Stopping criteria

Stop the test if:

• Pain increases sharply
• Apprehension becomes high
• The client reports slipping or instability that feels unsafe
• Neurological symptoms occur
• The client asks to stop
• The professional cannot control the arm safely

Safety notes

The test should be gentle and controlled. Avoid repeated strong traction, especially in irritable or recently unstable shoulders.

Positive and Negative Test Interpretation

A positive Inferior Sulcus Test may suggest inferior glenohumeral laxity. It is more meaningful when it reproduces the client’s familiar instability symptoms, apprehension, slipping sensation or matches a broader pattern of multidirectional instability.

However, a positive sulcus sign does not confirm symptomatic instability. Some asymptomatic clients have visible inferior laxity. Laxity is a physical finding; instability is usually related to symptoms, control, apprehension and function.

A negative Inferior Sulcus Test may reduce suspicion of marked inferior laxity, especially if other instability tests and history are also negative. However, it does not exclude anterior, posterior or functional instability.

The finding is more meaningful when interpreted with:

• History of dislocation or subluxation
• Apprehension
• Direction of symptoms
• Load-and-shift testing
• Apprehension/relocation testing
• Generalised joint laxity
• Shoulder strength
• Scapular control
• Sport or work demands
• Functional instability reports

Sensitivity, Specificity and Diagnostic Accuracy

Diagnostic accuracy varies depending on the sulcus size threshold and target condition.

Commonly cited evidence from Tzannes and Murrell reported:

Condition or presentation: Shoulder instability / inferior laxity assessment
Population: Shoulder instability assessment population
Test variation: Sulcus sign / Inferior Sulcus Test
Reference standard: Clinical instability assessment and related reference criteria
Sensitivity: Approximately 28% for a sulcus sign greater than 2 cm
Specificity: Approximately 97% for a sulcus sign greater than 2 cm
Positive likelihood ratio: Potentially useful when the sign is large and clinically relevant
Negative likelihood ratio: Limited usefulness because sensitivity is low
Key limitations: Laxity can be observed in asymptomatic people, and sulcus size alone does not define symptomatic instability.

Some summaries also describe a lower threshold, such as more than 1 cm, as more sensitive but less specific. This reinforces the importance of recording the size of the sulcus and the client’s symptom response rather than using a simple yes/no result.

Plain-language interpretation:

• A large sulcus sign may increase suspicion of inferior laxity when symptoms fit.
• A negative test does not exclude instability.
• A visible sulcus without symptoms may represent laxity rather than clinically relevant instability.
• The test is most useful when combined with history and other instability findings.

Reliability and Validity

Reliability evidence for the sulcus sign is mixed and standardisation remains important.

A study of shoulder instability and laxity testing reported that several shoulder instability tests showed better intertester reliability than the sulcus sign, and concluded that the sulcus sign needs further standardisation before acceptable evidence can be assumed.

Reliability may be affected by:

• Force magnitude
• Arm position
• Client relaxation
• Shoulder guarding
• Definition of sulcus size
• Visual versus palpated grading
• Examiner experience
• Whether symptoms or only translation are recorded

Validity is limited if the test is used alone. It has practical value as an inferior laxity observation but does not directly prove symptomatic multidirectional instability.

Reliability improves when the professional records:

• Arm position
• Force direction
• Sulcus grade
• Symptom response
• Apprehension
• Comparison side
• Client relaxation
• Test confidence

Common Errors and Limitations

Common errors include:

• Confusing laxity with symptomatic instability
• Applying inconsistent force
• Not recording sulcus grade
• Not recording apprehension
• Not comparing sides
• Testing when the client is guarding
• Treating asymptomatic laxity as pathology
• Not considering generalised joint laxity
• Using the test alone to make decisions
• Ignoring shoulder strength and scapular control

Limitations include:

• Low sensitivity at higher sulcus thresholds
• Laxity may be normal in some clients
• Reliability can be limited
• Force is difficult to standardise manually
• It does not identify labral or capsular pathology with certainty
• It does not assess dynamic shoulder control
• It should not be used alone for sport or work decisions

Practical Applications

The Inferior Sulcus Test may be useful for:

• Inferior shoulder laxity assessment
• Multidirectional instability assessment reasoning
• Side-to-side comparison
• Recording apprehension or instability symptoms
• Baseline and retest documentation
• Client education about laxity versus instability
• Deciding whether further shoulder assessment is needed

In Measurz, it can be recorded alongside apprehension/relocation testing, load-and-shift, Gagey test, shoulder range of motion, rotator cuff strength, scapular control and functional shoulder testing.

How to Record This in Measurz

Record:

• Test name: Inferior Sulcus Test / Sulcus Sign
• Side tested
• Arm position
• Result: positive, negative, unclear or unable to test
• Sulcus grade: none, less than 1 cm, 1–2 cm, greater than 2 cm
• Pain score
• Symptom location
• Apprehension
• Feeling of slipping or instability
• Whether symptoms were familiar
• Force direction
• Comparison side
• Generalised laxity notes if relevant
• Guarding or compensations
• Reason for stopping if relevant
• Related instability findings
• Confidence in interpretation
• Further assessment or referral notes if appropriate
• Retest date if relevant

Recording these details improves repeatability, communication, client education, assessment reasoning, monitoring over time, team consistency and reporting quality.

Related Tests / Internal Links

• Apprehension Test
• Relocation Test
• Load-and-Shift Test
• Gagey Test
• Posterior Apprehension Test
• Jerk Test
• Scapular Assistance Test
• Shoulder Range of Motion
• Shoulder Strength Testing
• Drop Arm Test
• Cervical Quadrant Test

FAQs

What does the Inferior Sulcus Test assess?

It assesses inferior translation of the humeral head and may support reasoning around inferior laxity or multidirectional instability.

What is a positive sulcus sign?

A positive finding is a visible or palpable sulcus below the acromion when inferior traction is applied to the arm.

Does a positive test diagnose shoulder instability?

No. It may indicate laxity, but symptomatic instability requires symptoms, apprehension, functional reports and other assessment findings.

Can a sulcus sign be normal?

Yes. Some asymptomatic people have inferior laxity, so the result must be interpreted in context.

What sulcus size is important?

A sulcus greater than 2 cm has been reported with high specificity but low sensitivity in commonly cited evidence. Size should be recorded, not overinterpreted.

Does a negative test exclude instability?

No. A negative sulcus sign does not exclude anterior, posterior, inferior or functional instability.

Should both shoulders be tested?

Yes. Side-to-side comparison is important.

What should it be combined with?

History, instability symptoms, apprehension testing, load-and-shift, generalised laxity assessment, strength testing and scapular control assessment.

Key Takeaways

The Inferior Sulcus Test assesses inferior shoulder laxity.

A visible sulcus may indicate inferior translation, but laxity is not the same as symptomatic instability.

A sulcus greater than 2 cm has been reported with low sensitivity and high specificity in commonly cited evidence.

A negative test does not exclude instability.

The test should be interpreted with history, apprehension, functional instability symptoms and other shoulder tests.

Measurz recording should include side, sulcus grade, pain, apprehension, symptom familiarity and comparison side.

References

Blonna, D., Bellato, E., Caranzano, F., Assom, M., Rossi, R., Castoldi, F., & Marmotti, A. (2018). Intertester reliability of clinical shoulder instability and laxity tests in subjects with and without self-reported shoulder problems. BMJ Open, 8(3), e018472. https://doi.org/10.1136/bmjopen-2017-018472

Hegedus, E. J., Goode, A. P., Cook, C. E., Michener, L., Myer, C. A., Myer, D. M., & Wright, A. A. (2012). 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. British Journal of Sports Medicine, 46(14), 964–978. https://doi.org/10.1136/bjsports-2012-091066

Jaggi, A., & Lambert, S. (2010). Rehabilitation for shoulder instability. British Journal of Sports Medicine, 44(5), 333–340. https://doi.org/10.1136/bjsm.2009.059311

Tzannes, A., & Murrell, G. A. C. (2002). Clinical examination of the unstable shoulder. Sports Medicine, 32(7), 447–457. https://doi.org/10.2165/00007256-200232070-00004