1. Introduction / Plain Theory

Shoulder Impingement Syndrome (SIS) refers to pain caused by mechanical compression of soft tissues (such as the rotator cuff tendons or subacromial bursa) between the humeral head and the acromion during shoulder elevation.

This “pinching” effect reduces the available subacromial space, leading to irritation, inflammation, or degeneration of the involved structures — particularly the supraspinatus tendon.

Impingement is one of the most common causes of shoulder pain, accounting for up to 44–65% of all shoulder complaints seen in primary care.

It often coexists with rotator cuff tendinopathy, but differs in mechanism:

• Impingement is primarily mechanical — a space or movement coordination issue.

• Tendinopathy is primarily degenerative — an overload and tissue adaptation problem.

Both are strongly influenced by posture, scapular control, and thoracic mobility — which makes osteopathic assessment particularly relevant.

2. Typical Symptoms and Functional Impact

• Pain at the front or side of the shoulder, sometimes radiating down the upper arm.

• Pain when lifting the arm, especially between 60°–120° of abduction (“painful arc”).

• Sharp discomfort when reaching overhead, behind the back, or across the body.

• Night pain, particularly when lying on the affected side.

• Weakness or fatigue during reaching, lifting, or throwing activities.

Functional impact:
Impingement can significantly limit daily function — dressing, lifting children, driving, or sports performance.
If untreated, chronic irritation can lead to rotator cuff tendinopathy or partial tearing, prolonging recovery and reducing shoulder stability.

Red flags:
Sudden loss of strength, trauma, or persistent night pain unresponsive to conservative care should prompt medical evaluation for possible cuff tear or other pathology.

3. Contributing Factors / Underlying Causes

Shoulder impingement results from a complex interaction between joint mechanics, muscle balance, and posture.

Common contributors include:

• Poor scapular control (reduced upward rotation or posterior tilt).

• Rounded shoulder posture (protracted scapula, shortened pectoral muscles).

• Thoracic spine stiffness, reducing overhead mobility.

• Muscle imbalance: overactive upper trapezius and anterior deltoid, weak lower trapezius and serratus anterior.

• Repetitive overhead activity: swimming, throwing, painting, or lifting.

• Acromial shape or bony spurs: reducing the subacromial space.

• Cervical and rib dysfunctions affecting shoulder coordination and neural input.

From an osteopathic perspective, impingement rarely occurs in isolation. It is part of a whole-body adaptation pattern — involving the spine, ribs, and breathing mechanics that influence shoulder motion and tension balance.

4. Osteopathic Approach

Osteopathic treatment aims to restore mobility, balance, and coordination across the entire shoulder complex to reduce impingement and promote natural tissue healing.

An osteopathic assessment may include:

• Evaluation of scapular rhythm, thoracic motion, and cervical alignment.

• Palpation for soft tissue tension in rotator cuff, deltoid, and pectoral regions.

• Gentle mobilisation of the glenohumeral, acromioclavicular, and sternoclavicular joints.

• Myofascial release to improve movement in the chest wall, ribs, and shoulder girdle.

• Functional and indirect techniques to calm pain and improve neuromuscular coordination.

• Breathing work and postural retraining to enhance shoulder stability.

• Guidance on gradual loading, ergonomics, and exercises to support recovery.

The goal is not merely to “open space” in the shoulder, but to restore harmony between motion, stability, and control — allowing pain-free, efficient function.

5. Scientific Evidence & References

Evidence supports manual therapy and targeted exercise as effective first-line treatments for shoulder impingement and rotator cuff-related pain.
Research shows that addressing scapular mechanics, thoracic mobility, and posture enhances recovery more effectively than local treatment alone.

Osteopathic and physiotherapy-based approaches focusing on mobility, load management, and motor control have been shown to reduce pain and improve function across both short and long terms.

References

1. Ludewig PM, Braman JP. Shoulder impingement: biomechanical considerations in rehabilitation. Man Ther. 2011;16(1):33–39. Link

2. Michener LA, McClure PW, Karduna AR. Anatomy and biomechanics of impingement syndrome: current concepts. J Athl Train. 2003;38(4):364–375. Link

3. Hanratty CE, et al. Manual therapy, exercise therapy, or both for patients with subacromial shoulder pain: systematic review and meta-analysis. BMJ Open. 2017;7(12):e018151. Link

4. Desmeules F, et al. Efficacy of exercise therapy in the treatment of rotator cuff tendinopathy: a systematic review and meta-analysis. J Orthop Sports Phys Ther. 2015;45(7):523–538. Link

5. Littlewood C, Malliaras P, Mawson S, May S, Walters SJ. Self-managed loaded exercise versus usual physiotherapy treatment for rotator cuff tendinopathy: randomized controlled trial. BMJ. 2014;349:g970. Link

6. Tozzi P. A unifying neuro-fasciagenic model of somatic dysfunction — underlying mechanisms and treatment. J Bodyw Mov Ther. 2015;19(2):254–265. Link

7. Degenhardt BF, Johnson JC, Fossum C, et al. Osteopathic manipulative treatment for shoulder pain: pragmatic pilot study. J Bodyw Mov Ther. 2017;21(4):857–865. Link

8. Xie Y, Chen Z, Yang Z, et al. Comparative efficacy of manual therapy interventions for subacromial shoulder pain: network meta-analysis. Front Pain Res. 2024;15:1507384. Link