Winging of the Scapula

Definition

Anatomy of Scapular Stabilization

Types and Causes

1. Medial Winging (Most Common)

• The long thoracic nerve passes down the lateral thoracic wall on the external surface of the serratus anterior, just deep to skin and subcutaneous fascia - making it highly vulnerable to trauma.
• The inferior angle and medial border of the scapula lift away from the chest wall, especially when the patient pushes forward with the arm.
• Normal arm elevation is also impaired (limited to ~15° from trapezius action alone).

• Pressure on the shoulder (carrying heavy loads - "rucksack paralysis")
• Direct trauma to shoulder or lateral thoracic wall (sports, falls, road traffic accidents)
• Cervical spine manipulation
• Repetitive overhead arm activities, weight lifting
• Iatrogenic: radical mastectomy (~10%), axillary node dissection, thoracotomy, first rib resection, chest tube insertion
• Neuralgic amyotrophy (Parsonage-Turner syndrome) - most common non-traumatic cause
• Rarely: Lyme disease, radiation therapy, familial brachial plexus neuropathy

In a review of 128 patients with unilateral winged scapula: 70 had long thoracic nerve palsy, 39 had spinal accessory nerve palsy, 5 had both, 5 had facioscapulohumeral dystrophy, and 11 had orthopedic causes. (Localization in Clinical Neurology, 8e)

2. Lateral Winging

• CN XI is vulnerable in the posterior triangle of the neck (bounded by the clavicle inferiorly, sternocleidomastoid anteriorly, and trapezius posteriorly - this is "Erb's point" danger zone).
• Features: shoulder drop, trapezius atrophy, inability to abduct arm >80°, neck/shoulder pain, and winging that is more prominent at rest and with arm elevation.
• Commonly injured during neck dissection surgery, lymph node biopsy in the posterior triangle, or trauma.

3. Dorsal Scapular Nerve / Rhomboid Paralysis

• Less common contributor; causes the inferior angle to rotate laterally.

Clinical Differentiation

Clinical Features

• At rest, the scapula may look normal.
• Winging is elicited by asking the patient to push the outstretched arms against a wall (for serratus anterior palsy) or to abduct/elevate the arm (for trapezius palsy).
• Weakness of the shoulder, fatigue on raising the arm above the head.
• Sharp pain radiating to the neck and upper arm (especially in stretch injuries).

Investigation

• EMG/NCS is the key electrodiagnostic tool - confirms denervation of serratus anterior or trapezius and identifies the level of nerve injury.
• Imaging (MRI shoulder/neck/brachial plexus) if structural cause suspected.

Management

• Conservative: Most cases (especially long thoracic neuropathy from neuralgic amyotrophy or trauma) are self-limited and resolve with physiotherapy over months to years.
• Surgical options (for persistent/refractory cases):
  • Nerve grafting or neurolysis
  • Muscle transfers (e.g., pectoralis minor transfer for serratus anterior palsy)
  • Scapulothoracic fusion (severe, refractory cases)
  • For rhomboid/trapezius palsy: Eden-Lange procedure (muscle transfer)