Shoulder impingement syndrome is one of the most common causes of shoulder pain, accounting for up to 65% of shoulder complaints. If you experience pain when reaching overhead, behind your back, or when lying on your shoulder at night — you may have shoulder impingement. The good news: the vast majority of cases resolve completely with the right conservative treatment — no surgery required.
What Is Shoulder Impingement?
The term "shoulder impingement" describes compression or irritation of the soft tissues within the subacromial space — the gap between the top of the humerus (upper arm bone) and the acromion (the bony projection of the shoulder blade). The structures most commonly affected include:
- The supraspinatus tendon (part of the rotator cuff)
- The subacromial bursa (fluid-filled sac that cushions the rotator cuff)
- The biceps tendon (long head)
Modern understanding has moved away from purely mechanical explanations. The current preferred term is subacromial pain syndrome — recognising that tendon degeneration, inflammation and altered movement patterns all contribute, rather than simple "impingement" from bone.
Causes of Shoulder Impingement
- Rotator cuff weakness: Weak external rotators (infraspinatus, teres minor) and serratus anterior allow the humeral head to migrate upward, reducing subacromial space
- Poor scapular mechanics: Winging or inadequate upward rotation of the scapula reduces the acromiohumeral distance during arm elevation
- Thoracic kyphosis: A rounded upper back tilts the scapula forward, effectively narrowing the subacromial space
- Overuse: Repetitive overhead activities (swimming, throwing, painting, gym training) can accumulate micro-trauma in the supraspinatus tendon
- Acromial morphology: Some people have a hooked (Type III) acromion that structurally reduces the subacromial space
Symptoms
- Pain with arm elevation, particularly between 60–120° (the "painful arc")
- Pain reaching behind the back or across the body
- Night pain — particularly when lying on the affected shoulder
- Weakness or inability to hold weight with the arm raised
- A positive Hawkins-Kennedy or Neer impingement test on clinical assessment
Chiropractic Treatment for Shoulder Impingement
- Glenohumeral joint mobilisation: Improving posterior capsule mobility and restoring normal joint arthrokinematics
- Acromioclavicular and sternoclavicular joint treatment: Addressing contributing restrictions in the shoulder complex
- Thoracic spine adjustment: Correcting thoracic kyphosis to improve scapular resting position and mechanics
- Soft tissue therapy: Releasing tight posterior capsule and pectoralis minor — key contributors to impingement mechanics
- Dry needling: Targeting trigger points in the rotator cuff and upper trapezius
Exercise Rehabilitation for Shoulder Impingement
Exercise rehabilitation is the cornerstone of long-term resolution. A progressive program typically addresses:
- Pain-free range of motion: Pendulum exercises, gentle passive range of motion
- Rotator cuff strengthening: External rotation with band, sidelying external rotation, prone Y/T/W
- Scapular stabilisation: Serratus anterior activation, low row, wall slides
- Posterior capsule stretching: Sleeper stretch, cross-body stretch
- Pectoralis minor stretching: Doorframe stretch, thoracic extension over foam roller
- Progressive overhead loading: Gradually reintroducing overhead activities as pain and strength improve
When Is Surgery Considered?
Surgery (subacromial decompression) is only considered after 3–6 months of comprehensive conservative care has failed to produce adequate improvement. Recent research (including the landmark CSAW trial) questions whether subacromial decompression surgery outperforms sham surgery and structured physiotherapy — making conservative management even more compelling as the first line of treatment.
