Shoulder Impingement & ACJ Examination

Examiner Favorite

Impingement syndrome is the most common cause of shoulder pain. Examiners expect you to differentiate between subacromial (extrinsic) impingement and internal (intrinsic) impingement, understand the Neer and Hawkins tests, and recognize ACJ pathology with the cross-body adduction test.

Impingement & ACJ Examination Summary

High-Yield Exam Summary

Impingement Stages (Neer)

•Stage I: Edema/hemorrhage (under 25 years, reversible)
•Stage II: Fibrosis/tendinitis (25-40 years)
•Stage III: Bone spurs/tendon rupture (over 40 years)

Impingement Tests

•Neer test (passive forward flexion)
•Hawkins-Kennedy test (IR in 90° flexion)
•Painful arc (60-120°)
•Jobe's test (may be positive)

ACJ Tests

•Cross-body adduction
•ACJ palpation tenderness
•O'Brien's test (also tests labrum)
•Paxinos test

Key Differentiators

•Painful arc location (subacromial 60-120°, ACJ above 120°)
•Local anesthetic injection response
•X-ray findings (ACJ OA, subacromial spurs)

Introduction

Key Concepts

Subacromial Impingement Syndrome:

Mechanical compression of rotator cuff under coracoacromial arch
Most common cause of shoulder pain in adults
Spectrum from tendinitis to full-thickness tears

Causes of Impingement:

Extrinsic: Structural narrowing (type III acromion, AC osteophytes, os acromiale)
Intrinsic: Tendon degeneration, weakness, overhead activities
Secondary: Instability, scapular dyskinesia

ACJ Pathology:

Common site of OA (especially in laborers, weightlifters)
May coexist with impingement
Can be primary pain generator or contribute to impingement

Clinical Assessment

History Clues

Subacromial Impingement:

Pain with overhead activities
Night pain (lying on affected side)
Painful arc with arm elevation
Gradual onset (unless acute on chronic)
May have weakness if cuff involved

ACJ Pain:

Pain localized to "top of shoulder"
Aggravated by cross-body reaching
Pain with overhead pressing (gym)
May have clicking or grinding

Impingement Tests

Neer Impingement Test

Subacromial impingement

Technique

1Patient seated or standing
2Examiner stabilizes scapula with one hand
3Passively forward flex arm to maximum (thumb pointing down)
4Greater tuberosity impinges under anterior acromion

Positive Sign

Pain reproduced at end of forward flexion

Indicates

Subacromial impingement (anterior acromion compression)

Diagnostic Accuracy

Sensitivity79%

Ability to detect true positives

Specificity53%

Ability to exclude false positives

Hawkins-Kennedy Test

Subacromial impingement

Technique

1Patient seated or standing
2Arm forward flexed to 90°, elbow flexed 90°
3Forcibly internally rotate the shoulder (push forearm down)

Positive Sign

Pain reproduced with internal rotation

Indicates

Subacromial impingement (greater tuberosity impinges under coracoacromial ligament)

Diagnostic Accuracy

Sensitivity79%

Ability to detect true positives

Specificity59%

Ability to exclude false positives

Key Concept

Neer vs Hawkins:

Both test subacromial impingement
Neer: Anterior acromion compression (pure forward flexion)
Hawkins: Coracoacromial ligament compression (flexion + IR)
Using both increases sensitivity (if either positive)

Painful Arc Test

Subacromial pathology

Technique

1Patient actively abducts arm from side to overhead
2Observe for pain throughout the arc of motion

Positive Sign

Pain between 60-120° abduction (subacromial arc)

Indicates

Subacromial impingement. Pain above 120° suggests ACJ pathology

Diagnostic Accuracy

Sensitivity74%

Ability to detect true positives

Specificity81%

Ability to exclude false positives

Neer Impingement Injection Test

Confirm subacromial source of pain

Technique

1Perform Neer test - note pain level
2Inject 10ml local anesthetic into subacromial space
3Wait 5-10 minutes
4Repeat Neer test

Positive Sign

Significant reduction in pain (greater than 50%)

Indicates

Confirms subacromial space as pain source (diagnostic and therapeutic)

Diagnostic Accuracy

Sensitivity95%

Ability to detect true positives

Specificity85%

Ability to exclude false positives

ACJ Tests

Cross-Body Adduction Test

ACJ pathology

Technique

1Patient seated or standing
2Arm forward flexed to 90°
3Passively adduct arm across body toward opposite shoulder

Positive Sign

Pain localized to ACJ (top of shoulder)

Indicates

ACJ arthritis, ACJ sprain, or distal clavicle pathology

Diagnostic Accuracy

Sensitivity77%

Ability to detect true positives

Specificity79%

Ability to exclude false positives

ACJ Palpation

ACJ pathology

Technique

1Identify ACJ (palpate along clavicle to lateral end)
2ACJ is approximately 2-3cm medial to lateral shoulder edge
3Apply direct pressure to joint

Positive Sign

Point tenderness directly over ACJ

Indicates

ACJ arthritis, sprain, or osteolysis

Diagnostic Accuracy

Sensitivity96%

Ability to detect true positives

Specificity10%

Ability to exclude false positives

O'Brien's Test (Active Compression)

ACJ pathology and superior labral (SLAP) lesions

Technique

1Arm forward flexed 90°, adducted 10-15° across midline
2Elbow fully extended, thumb pointing DOWN (pronated)
3Patient resists downward pressure
4Repeat with thumb UP (supinated)

Positive Sign

Pain with thumb DOWN that is relieved with thumb UP. Pain at ACJ = ACJ pathology. Deep pain = SLAP lesion

Indicates

ACJ pathology (superficial pain) or SLAP tear (deep pain)

Diagnostic Accuracy

Sensitivity63%

Ability to detect true positives

Specificity73%

Ability to exclude false positives

Paxinos Test

ACJ pathology

Technique

1Patient seated, arm relaxed at side
2Examiner places thumb under posterolateral acromion
3Index and middle fingers over mid-clavicle
4Apply anterosuperior pressure with thumb while pushing down on clavicle

Positive Sign

Pain reproduced at ACJ

Indicates

ACJ pathology

Diagnostic Accuracy

Sensitivity79%

Ability to detect true positives

Specificity50%

Ability to exclude false positives

Internal Impingement

Internal (Posterosuperior) Impingement

Definition:

Impingement of articular surface of rotator cuff against posterosuperior glenoid
Occurs in late cocking phase of throwing

Population:

Young overhead athletes (throwers, swimmers, tennis)
Different from subacromial impingement

Examination:

Pain in apprehension position (90° abduction, maximum external rotation)
Posterior shoulder pain (not anterolateral like subacromial)
May have GIRD (glenohumeral internal rotation deficit)

Posterior Impingement Test

Internal (posterosuperior) impingement

Technique

1Patient supine, shoulder at edge of bed
2Arm abducted 90-110°, elbow flexed 90°
3Maximally externally rotate the arm
4Apply gentle anterior to posterior pressure on proximal humerus

Positive Sign

Posterior shoulder pain reproduced

Indicates

Internal impingement (articular cuff impinges on posterosuperior glenoid)

Diagnostic Accuracy

Sensitivity76%

Ability to detect true positives

Specificity85%

Ability to exclude false positives

Differential Diagnosis

condition	painLocation	painfulArc	tests
Subacromial Impingement	Anterolateral	60-120°	Neer +, Hawkins +
ACJ Arthritis	Top of shoulder	Above 120°	Cross-body +, ACJ tender
Rotator Cuff Tear	Anterolateral	Yes	Weakness, lag signs if complete
Calcific Tendinitis	Anterolateral (acute)	Variable	Severe pain, X-ray shows calcification
Adhesive Capsulitis	Global	No (stiff)	Global restriction, ER most limited
Cervical Radiculopathy	Radiating	No	Spurling's +, dermatomal pattern

Summary Presentation

VIVA SCENARIOStandard

Presenting Your Findings

EXAMINER

"52-year-old painter with 6-month history of right shoulder pain, worse with overhead work."

KEY POINTS TO SCORE

Painful arc 60-120° = subacromial; above 120° = ACJ

Neer and Hawkins both positive increases sensitivity

Impingement injection test confirms subacromial source

Always assess rotator cuff strength (may coexist)

COMMON TRAPS

✗Missing ACJ pathology as co-contributor

✗Not differentiating impingement from rotator cuff tear

✗Forgetting internal impingement in young throwers

✗Missing cervical spine referral

Impingement vs ACJ Pain

feature	impingement	acj
Pain Location	Anterolateral deltoid	Top of shoulder (localized)
Painful Arc	60-120° (mid-arc)	Above 120° (high arc)
Night Pain	Yes (lying on side)	Less common
Provocative Test	Neer, Hawkins	Cross-body adduction
Palpation	Greater tuberosity tender	ACJ directly tender
Injection Response	Subacromial injection helps	ACJ injection helps

Examiner Tips

Scoring High in Impingement Examination

High-Yield Exam Summary

Do

•Perform both Neer AND Hawkins
•Note painful arc location (mid vs high)
•Palpate ACJ directly
•Test rotator cuff strength
•Mention injection test as diagnostic option

Don't

•Confuse subacromial and ACJ pain
•Miss internal impingement in throwers
•Forget to assess rotator cuff integrity
•Ignore cervical spine as referral source
•Rely on single test - use combination

Shoulder Impingement & ACJ Examination

Examiner Favorite

Impingement & ACJ Examination Summary

High-Yield Exam Summary

Impingement Stages (Neer)

•Stage I: Edema/hemorrhage (under 25 years, reversible)
•Stage II: Fibrosis/tendinitis (25-40 years)
•Stage III: Bone spurs/tendon rupture (over 40 years)

Impingement Tests

•Neer test (passive forward flexion)
•Hawkins-Kennedy test (IR in 90° flexion)
•Painful arc (60-120°)
•Jobe's test (may be positive)

ACJ Tests

•Cross-body adduction
•ACJ palpation tenderness
•O'Brien's test (also tests labrum)
•Paxinos test

Key Differentiators

•Painful arc location (subacromial 60-120°, ACJ above 120°)
•Local anesthetic injection response
•X-ray findings (ACJ OA, subacromial spurs)

Introduction

Key Concepts

Subacromial Impingement Syndrome:

Mechanical compression of rotator cuff under coracoacromial arch
Most common cause of shoulder pain in adults
Spectrum from tendinitis to full-thickness tears

Causes of Impingement:

Extrinsic: Structural narrowing (type III acromion, AC osteophytes, os acromiale)
Intrinsic: Tendon degeneration, weakness, overhead activities
Secondary: Instability, scapular dyskinesia

ACJ Pathology:

Common site of OA (especially in laborers, weightlifters)
May coexist with impingement
Can be primary pain generator or contribute to impingement

Clinical Assessment

History Clues

Subacromial Impingement:

Pain with overhead activities
Night pain (lying on affected side)
Painful arc with arm elevation
Gradual onset (unless acute on chronic)
May have weakness if cuff involved

ACJ Pain:

Pain localized to "top of shoulder"
Aggravated by cross-body reaching
Pain with overhead pressing (gym)
May have clicking or grinding

Impingement Tests

Neer Impingement Test

Subacromial impingement

Technique

1Patient seated or standing
2Examiner stabilizes scapula with one hand
3Passively forward flex arm to maximum (thumb pointing down)
4Greater tuberosity impinges under anterior acromion

Positive Sign

Pain reproduced at end of forward flexion

Indicates

Subacromial impingement (anterior acromion compression)

Diagnostic Accuracy

Sensitivity79%

Ability to detect true positives

Specificity53%

Ability to exclude false positives

Hawkins-Kennedy Test

Subacromial impingement

Technique

1Patient seated or standing
2Arm forward flexed to 90°, elbow flexed 90°
3Forcibly internally rotate the shoulder (push forearm down)

Positive Sign

Pain reproduced with internal rotation

Indicates

Subacromial impingement (greater tuberosity impinges under coracoacromial ligament)

Diagnostic Accuracy

Sensitivity79%

Ability to detect true positives

Specificity59%

Ability to exclude false positives

Key Concept

Neer vs Hawkins:

Both test subacromial impingement
Neer: Anterior acromion compression (pure forward flexion)
Hawkins: Coracoacromial ligament compression (flexion + IR)
Using both increases sensitivity (if either positive)

Painful Arc Test

Subacromial pathology

Technique

1Patient actively abducts arm from side to overhead
2Observe for pain throughout the arc of motion

Positive Sign

Pain between 60-120° abduction (subacromial arc)

Indicates

Subacromial impingement. Pain above 120° suggests ACJ pathology

Diagnostic Accuracy

Sensitivity74%

Ability to detect true positives

Specificity81%

Ability to exclude false positives

Neer Impingement Injection Test

Confirm subacromial source of pain

Technique

1Perform Neer test - note pain level
2Inject 10ml local anesthetic into subacromial space
3Wait 5-10 minutes
4Repeat Neer test

Positive Sign

Significant reduction in pain (greater than 50%)

Indicates

Confirms subacromial space as pain source (diagnostic and therapeutic)

Diagnostic Accuracy

Sensitivity95%

Ability to detect true positives

Specificity85%

Ability to exclude false positives

ACJ Tests

Cross-Body Adduction Test

ACJ pathology

Technique

1Patient seated or standing
2Arm forward flexed to 90°
3Passively adduct arm across body toward opposite shoulder

Positive Sign

Pain localized to ACJ (top of shoulder)

Indicates

ACJ arthritis, ACJ sprain, or distal clavicle pathology

Diagnostic Accuracy

Sensitivity77%

Ability to detect true positives

Specificity79%

Ability to exclude false positives

ACJ Palpation

ACJ pathology

Technique

1Identify ACJ (palpate along clavicle to lateral end)
2ACJ is approximately 2-3cm medial to lateral shoulder edge
3Apply direct pressure to joint

Positive Sign

Point tenderness directly over ACJ

Indicates

ACJ arthritis, sprain, or osteolysis

Diagnostic Accuracy

Sensitivity96%

Ability to detect true positives

Specificity10%

Ability to exclude false positives

O'Brien's Test (Active Compression)

ACJ pathology and superior labral (SLAP) lesions

Technique

1Arm forward flexed 90°, adducted 10-15° across midline
2Elbow fully extended, thumb pointing DOWN (pronated)
3Patient resists downward pressure
4Repeat with thumb UP (supinated)

Positive Sign

Pain with thumb DOWN that is relieved with thumb UP. Pain at ACJ = ACJ pathology. Deep pain = SLAP lesion

Indicates

ACJ pathology (superficial pain) or SLAP tear (deep pain)

Diagnostic Accuracy

Sensitivity63%

Ability to detect true positives

Specificity73%

Ability to exclude false positives

Paxinos Test

ACJ pathology

Technique

1Patient seated, arm relaxed at side
2Examiner places thumb under posterolateral acromion
3Index and middle fingers over mid-clavicle
4Apply anterosuperior pressure with thumb while pushing down on clavicle

Positive Sign

Pain reproduced at ACJ

Indicates

ACJ pathology

Diagnostic Accuracy

Sensitivity79%

Ability to detect true positives

Specificity50%

Ability to exclude false positives

Internal Impingement

Internal (Posterosuperior) Impingement

Definition:

Impingement of articular surface of rotator cuff against posterosuperior glenoid
Occurs in late cocking phase of throwing

Population:

Young overhead athletes (throwers, swimmers, tennis)
Different from subacromial impingement

Examination:

Pain in apprehension position (90° abduction, maximum external rotation)
Posterior shoulder pain (not anterolateral like subacromial)
May have GIRD (glenohumeral internal rotation deficit)

Posterior Impingement Test

Internal (posterosuperior) impingement

Technique

1Patient supine, shoulder at edge of bed
2Arm abducted 90-110°, elbow flexed 90°
3Maximally externally rotate the arm
4Apply gentle anterior to posterior pressure on proximal humerus

Positive Sign

Posterior shoulder pain reproduced

Indicates

Internal impingement (articular cuff impinges on posterosuperior glenoid)

Diagnostic Accuracy

Sensitivity76%

Ability to detect true positives

Specificity85%

Ability to exclude false positives

Differential Diagnosis

condition	painLocation	painfulArc	tests
Subacromial Impingement	Anterolateral	60-120°	Neer +, Hawkins +
ACJ Arthritis	Top of shoulder	Above 120°	Cross-body +, ACJ tender
Rotator Cuff Tear	Anterolateral	Yes	Weakness, lag signs if complete
Calcific Tendinitis	Anterolateral (acute)	Variable	Severe pain, X-ray shows calcification
Adhesive Capsulitis	Global	No (stiff)	Global restriction, ER most limited
Cervical Radiculopathy	Radiating	No	Spurling's +, dermatomal pattern

Summary Presentation

VIVA SCENARIOStandard

Presenting Your Findings

EXAMINER

"52-year-old painter with 6-month history of right shoulder pain, worse with overhead work."

KEY POINTS TO SCORE

Painful arc 60-120° = subacromial; above 120° = ACJ

Neer and Hawkins both positive increases sensitivity

Impingement injection test confirms subacromial source

Always assess rotator cuff strength (may coexist)

COMMON TRAPS

✗Missing ACJ pathology as co-contributor

✗Not differentiating impingement from rotator cuff tear

✗Forgetting internal impingement in young throwers

✗Missing cervical spine referral

Impingement vs ACJ Pain

feature	impingement	acj
Pain Location	Anterolateral deltoid	Top of shoulder (localized)
Painful Arc	60-120° (mid-arc)	Above 120° (high arc)
Night Pain	Yes (lying on side)	Less common
Provocative Test	Neer, Hawkins	Cross-body adduction
Palpation	Greater tuberosity tender	ACJ directly tender
Injection Response	Subacromial injection helps	ACJ injection helps

Examiner Tips

Scoring High in Impingement Examination

High-Yield Exam Summary

Do

•Perform both Neer AND Hawkins
•Note painful arc location (mid vs high)
•Palpate ACJ directly
•Test rotator cuff strength
•Mention injection test as diagnostic option

Don't

•Confuse subacromial and ACJ pain
•Miss internal impingement in throwers
•Forget to assess rotator cuff integrity
•Ignore cervical spine as referral source
•Rely on single test - use combination

Shoulder Impingement & ACJ Examination

Shoulder Impingement & ACJ Examination

Quick Reference One-Pager

Impingement & ACJ Examination Summary

Impingement Stages (Neer)

Impingement Tests

ACJ Tests

Key Differentiators

Introduction

Key Concepts

Clinical Assessment

History Clues

Impingement Tests

Neer Impingement Test

Technique

Positive Sign

Indicates

Diagnostic Accuracy

Hawkins-Kennedy Test

Technique

Positive Sign

Indicates

Diagnostic Accuracy

Painful Arc Test

Technique

Positive Sign

Indicates

Diagnostic Accuracy

Neer Impingement Injection Test

Technique

Positive Sign

Indicates

Diagnostic Accuracy

ACJ Tests

Cross-Body Adduction Test

Technique

Positive Sign

Indicates

Diagnostic Accuracy

ACJ Palpation

Technique

Positive Sign

Indicates

Diagnostic Accuracy

O'Brien's Test (Active Compression)

Technique

Positive Sign

Indicates

Diagnostic Accuracy

Paxinos Test

Technique

Positive Sign

Indicates

Diagnostic Accuracy

Internal Impingement

Internal (Posterosuperior) Impingement

Posterior Impingement Test

Technique

Positive Sign

Indicates

Diagnostic Accuracy

Differential Diagnosis

Summary Presentation

Presenting Your Findings

Impingement vs ACJ Pain

Examiner Tips

Scoring High in Impingement Examination

Do

Don't

Shoulder Impingement & ACJ Examination

Shoulder Impingement & ACJ Examination

Quick Reference One-Pager

Impingement & ACJ Examination Summary

Impingement Stages (Neer)

Impingement Tests

ACJ Tests

Key Differentiators

Introduction

Key Concepts

Clinical Assessment