Snapping scapula syndrome

• Scapulothoracic crepitus

• 726.10 Disorders of bursae and tendons in shoulder region unspecified

• M75.50 Bursitis of unspecified shoulder

• 4E: Impaired Joint Mobility, Motor Function, Muscle Performance, and Range of Motion Associated With Localized Inflammation

Description

• Scapulothoracic joint not a true synovial joint
• 2:1 ratio of glenohumeral (GH) elevation to scapulothoracic elevation
• Scapulothoracic motion produces a snapping, popping, crepitus sound.
• Scapula has the greatest number of muscles attached to it than any other bone.
• Scapula dysrhythmia can cause friction along the muscles and ribs.
• Can be a result of serratus anterior muscle dysfunction
• Injury to long thoracic nerve

Essentials of Diagnosis

• Often asymptomatic
• Winging can help identify a dysfunction possibly occurring in the shoulder
• Symptoms of pain and weakness
• Can be a result of a brachial plexus injury
• Parsonage-Turner syndrome (brachial neuritis) underlying

General Considerations

• Postural changes of the thoracic spine and ribcage: scoliosis
• Loss of serratus anterior muscle
• Weakness of trapezius strength, scapular stabilizers
• Commonly associated with presence of other orthopedic pathologies such as subacromial impingement syndrome, rotator cuff pathology, and labral pathology.
• Creates an abnormal scapulothoracic rhythm
• Commonly associated with repeated overhead or overuse activities
• Full history of symptoms, medical history screening, and differential shoulder orthopedic examination will ensure appropriate diagnosis.

Demographics

• Non-specific
• Overhead athletes

Signs and Symptoms

• Pain
• Symptoms of bursitis
• Crepitus
• Muscle spasm along rib cage
• Weakness is commonly noted with functional reaching tasks
• Scapula instability, moving away from rib cage

Functional Limitations

• Inability to raise or lower arms without the scapula’s inferior angle tilting away from rib cage
• Pain/limitation with:
  • Overhead activities
  • Reaching
  • Lifting
  • Dressing and grooming
  • Sustained or repetitive shoulder activities

Possible Contributing Causes

• Increased thoracic kyphosis and sub-optimal posture
• Luschka tubercle
• Sprengel’s deformity
• Abnormally shaped rib cage: scoliosis
• Repetitive overhead activities
• Posterior shoulder capsule tightness
• Inferior angle tilting of the scapula
• Instability of the scapula to the thoracic wall
• Muscle atrophy
• Pectoralis minor tightness
• Poor neuromuscular control: nerve injury
• Non-traumatic injury to the long thoracic nerve
  • Influenza
  • Drug overdose
• Traumatic injury to the long thoracic nerve
  • Impact injury
  • Stretch to cervical spine
  • Electrical shock
  • Mastectomy with axillary node dissection
• Brachial neuritis (Parsonage-Turner syndrome)

Differential Diagnosis

• Winging scapula
• Scapula alata
• Facioscapulohumeral muscular dystrophy (FSH)
• Serratus anterior palsy
• Cervical radiculopathy, C5-8
• Referred pain from lungs or diaphragm
• Rotator cuff pathology (tendonitis, full- or partial-thickness tear)
• GH instability
• Labral tear
• Rib fracture
• Neuropathy
• Internal impingement
• Chondrosarcoma
• Elastofibroma

• Diagnosis made based on orthopedic special tests, signs and symptoms, imaging studies, and exclusion of differential diagnosis.
  • Push-ups test
  • Serratus wall test

Medications