Snapping Scapula Syndrome

Understanding the Scapulothoracic Joint and Snapping Scapula Syndrome:

Anatomy of the Scapulothoracic Joint

• Definition:
  The scapulothoracic joint is afunctional articulation where the scapula (shoulder blade) glides over the ribs, rather than a true anatomical joint with cartilage and ligaments.
• Components:
  • Scapula:rests on ribs 2–7, shaped like a flat triangle with three borders (superior, axillary/lateral, vertebral/medial) and three angles (superomedial, inferomedial, lateral/glenoid).
  • Thoracic Wall:ribs and muscles forming the chest wall.
  • Musculature:stabilises and moves the scapula since no direct bone or ligament connection exists.
• Key Scapular Features:
  • Acromion: lateral projection forming the shoulder’s highest point.
  • Coracoid Process: hook-like projection serving as muscle attachment.
  • Spine of scapula: ridge dividing posterior scapula.
  • Glenoid: shallow socket articulating with the humeral head, slightly tilted anteriorly.
• Neurovascular Landmarks:
  • Scapular notch and spinoglenoid notch transmit the suprascapular nerve and artery.
• Musculature:
  Primary muscles include:
  • Serratus anterior(protraction and upward rotation),
  • Trapezius(elevation, retraction, upward rotation),
  • Rhomboids(retraction and elevation),
  • Levator scapulae(elevation),
  • Pectoralis minor(protraction and depression),
  • Subclavius.
• Bursae:
  Fluid-filled sacs reducing friction between muscles and bones.
  • Primary: scapulothoracic (infraserratus) and subscapularis (supraserratus) bursae.
  • Minor bursae may form pathologically causing symptoms.

Function and Biomechanics of the Shoulder Complex

• Joints involved:Glenohumeral, acromioclavicular, sternoclavicular, scapulothoracic.
• Scapular Movement Degrees of Freedom:
  The scapula moves in six directions:
  • Translatory:protraction/retraction (forward/backward), elevation/depression (up/down).
  • Rotatory:upward/downward rotation, anterior/posterior tipping.
• Normal Scapular Position:
  Slightly upward rotated (~5°), internally rotated (30–45°), anteriorly tilted (~13°).
• Scapulohumeral Rhythm:
  Coordinated arm movement pattern; for every 3° of arm abduction, 2° occurs at the glenohumeral joint and 1° at the scapulothoracic joint (ratio 2:1).
• Clinical Significance:
  Proper scapular movement prevents impingement and supports shoulder stability.

Scapular Dyskinesis

• Definition:
  Abnormal scapular movement or positioning during shoulder motion.
• Causes:
  Muscle imbalances, nerve injuries (e.g., long thoracic nerve palsy), anatomical variations, previous shoulder injuries.
• Consequences:
  May cause shoulder impingement, instability, or rotator cuff tears.
• Compensatory Mechanisms:
  Sometimes scapular dyskinesis develops to compensate for other shoulder dysfunction.
• Types of Winging:
  • Medial winging: often due to serratus anterior paralysis.
  • Lateral winging: related to trapezius weakness or spinal accessory nerve injury.

Snapping Scapula Syndrome (SSS)

• Definition:
  Condition characterised by painful clicking, grinding, or snapping of the scapula during movement.
• Causes:
  • Osseous:Luschka Tubercle (bony hook on scapula), osteochondroma (benign bone tumour), abnormal scapular angulation.
  • Soft tissue:bursitis (inflammation of bursae), muscle imbalance, elastofibroma dorsi (benign soft tissue tumour).
• Symptoms:
  Audible/palpable snapping with pain at the scapula’s superomedial or inferior angle, worse with overhead activity.
• Physical Exam:
  Tenderness over scapula borders, reproduction of symptoms with scapular movement.

Diagnosis and Assessment

• Clinical Exam:
  Observation for asymmetry, palpation of scapula movement, special tests like:
  • Scapular Assistance Test (SAT):manual help with scapular rotation reduces pain.
  • Scapular Retraction Test (SRT):assesses rotator cuff strength with scapular support.
  • Lateral Scapular Slide Test (LSST):measures scapular position differences.
• Imaging:
  • Radiographs: exclude bone abnormalities but limited for soft tissues.
  • CT scan: detailed bony morphology, especially 3D reconstruction.
  • MRI: preferred for soft tissue pathology including bursitis and muscle tears.
  • Ultrasound: may help differentiate bursitis or soft tissue masses.
  • EMG: to rule out nerve palsies.
• Diagnostic Challenge:
  SSS is often difficult to diagnose due to subtle signs and overlapping conditions.

Treatment Approaches

• First-line:Conservative management for at least 6 months.
• Conservative Care:
  • Activity modification, rest, NSAIDs for inflammation.
  • Physical therapy focusing on posture correction, stretching tight muscles, strengthening weak scapular stabilisers (e.g., serratus anterior, rhomboids).
  • Local corticosteroid injections into bursae may reduce inflammation and aid diagnosis.
• Surgical Intervention:
  • Indicated after failed conservative therapy or significant anatomical abnormalities.
  • Procedures include bursectomy, partial resection of the superomedial scapular angle, muscle transfers.
  • Arthroscopic surgery is preferred for less pain and quicker recovery.
  • Careful protection of nerves (e.g., suprascapular nerve) during surgery is essential.
• Postoperative Rehabilitation:
  Gradual restoration of motion, strengthening, and functional use.
• Prognosis:
  Conservative treatment successful in most cases; surgery success rates 70–75%.

Prevention and Maintenance

• Maintain good posture and ergonomics.
• Modify activities that stress the scapulothoracic joint.
• Regular exercises to strengthen scapular stabilisers and maintain flexibility.
• Professional physical therapy guidance is advised for tailored programmes.

Glossary of Key Terms

See attached glossary for definitions of anatomical structures, motions, clinical tests, and pathologies.

Clinical Pearls / Key Points

• The scapulothoracic joint is afunctional joint relying on muscles and bursae, not ligaments or cartilage.
• Scapulohumeral rhythm is crucial for full arm elevation and shoulder health.
• Scapular dyskinesis is both a cause and consequence of shoulder pathology.
• Snapping Scapula Syndrome results from bony or soft tissue abnormalities causing painful scapular motion.
• Diagnosis requires careful clinical and imaging assessment.
• Conservative treatment, especially physical therapy, is first-line. Surgery is reserved for resistant cases.

Patient FAQs

Q: Why does my shoulder snap or click?
A: This may be due to Snapping Scapula Syndrome, where the shoulder blade rubs or clicks against the ribs, sometimes causing pain.

Q: Is surgery always needed for snapping scapula?
A: No, most cases improve with rest, physical therapy, and anti-inflammatory treatments. Surgery is only for severe or persistent symptoms.

Q: How can physical therapy help my shoulder?
A: Therapy focuses on strengthening muscles around your shoulder blade and improving posture to reduce abnormal movements and pain.

Call-to-Action

For exercise videos, detailed shoulder care guides, and specialist consultations, visit www.TheArmDoc.co.uk. To book an appointment, call 020 3384 5588 or email Info@TheArmDoc.co.uk.

Disclaimer

This guide is for educational purposes only and does not replace professional medical advice. If you experience shoulder pain or dysfunction, please consult a qualified healthcare professional.