Shoulder
Shoulder Impingement Syndrome
어깨 충돌증후군
Subacromial compression of the rotator cuff during arm elevation — most common shoulder diagnosis
- How common
- Very Common
- Typical age
- Ages 30–60
What is it?
The supraspinatus and subacromial bursa are compressed between the greater tuberosity and anterior acromion during arm elevation (60–120°).
Commonly affected: Supraspinatus tendon and subacromial bursa
How it develops
- Anatomic NarrowingSubacromial space is narrow — supraspinatus passes through during elevation
- Repetitive ImpingementOverhead activities compress supraspinatus against anterior acromion repeatedly
- Bursitis + TendinopathySubacromial bursitis and supraspinatus tendinopathy develop from chronic impingement
- Progression to TearUntreated impingement can progress to partial or full-thickness RC tear
Symptoms
- Painful Arc (60–120°)Pain specifically during 60–120° of active abduction — classic for impingement
- Anterior Shoulder PainAnterior and lateral shoulder pain — worse with reaching or overhead activities
- Night PainPain lying on affected shoulder at night
- Limited Overhead ActivityDifficulty with overhead work, dressing, or reaching behind back
How it is examined
- Neer Impingement SignPassive forward flexion with internally rotated arm reproduces pain — anterior impingement
- Hawkins-Kennedy TestShoulder/elbow 90° flexion + forced internal rotation — reproduces impingement pain
- Positive Neer Impingement Injection TestSubacromial lidocaine injection provides pain relief — confirms subacromial origin
Imaging
X-ray evaluates acromial morphology (type I flat, II curved, III hooked — hook = highest risk), AHD, and os acromiale.
- Hooked acromion type III
- Acromial spur
- Acromiohumeral distance measurement
MRI shows subacromial bursal fluid, tendon signal changes, and partial/full-thickness tears. Guides surgical planning.
- Subacromial bursal effusion
- Supraspinatus tendon T2 signal changes
- Partial or full-thickness tear?
Non-surgical care
- PT + Posture CorrectionPosterior capsule stretching, RC strengthening, scapular stabilization — mainstay
- NSAIDs + Subacromial InjectionSubacromial corticosteroid injection provides rapid pain relief for rehab
- Activity ModificationReduce overhead activities; correct forward head/rounded shoulder posture
Conservative options are generally tried first. Medications listed here can have side effects — discuss them with your prescriber.
When surgery is considered
Failed 6 months physical therapy and injections
Procedures that may be discussed
- Arthroscopic acromioplasty + bursectomy
- Coracoacromial ligament release
Outlook
80–90% resolve with conservative care within 6–12 months.