Anatomy
- Formed from the C5, C6 and C7 roots
- Passes through or behind scalenus medius
- Descends on the lateral chest wall on the superficial surface of serratus anterior near the midaxillary line
- Its long course makes it prone to traction
- C5 and C6 roots join within scalenus medius and C7 joins on its surface
Motor Supply
- Serratus anterior
Clinical Features
- Medial scapular winging, accentuated by a wall push up
- Difficulty with forward elevation above shoulder height
- Causes include heavy loads carried on the shoulder, traction in sport, neuralgic amyotrophy, axillary node clearance, first rib resection and thoracic surgery
- Lateral winging points instead to trapezius weakness from a spinal accessory nerve injury
- Dorsal scapular nerve injury weakens the rhomboids and gives subtle medial winging
Investigations
- EMG of serratus anterior confirms the diagnosis and monitors recovery
- MRI or ultrasound to exclude a mass along its course
Management
- Most cases recover over 1 to 2 years with physiotherapy
- Transfer of the sternal head of pectoralis major to the inferior angle of the scapula for persistent winging
- Scapulothoracic fusion for failed transfer or global shoulder girdle weakness
- Scapular bracing is poorly tolerated
- Avoid heavy overhead loading during recovery
Structures at Risk
- Axillary dissection and lateral thoracotomy incisions
- Transaxillary first rib resection
Reviewed by Professor Phong Tran, Head of Orthopaedic Surgery, Western Health. Last updated 10 October 2026.