II. Epidemiology
- Uncommon to rare
III. Pathophysiology
- Scapular Winging results from innervation loss
- Long Thoracic Nerve (most common, C5-7 origin)
- Spinal Accessory nerve (Cranial Nerve 11)
- Innervates levator Scapulae and rhomboid Muscles
- Iatrogenic causes are most common (e.g. Lymph Node or Neck Mass excision)
- Dorsal Scapular Nerve (C4-5 origin)
- Innervates trapezius Muscle
- Injury occurs with strenuous activity or lifting
- Results in paralysis of the trapezius Muscle, rhomboid Muscles, or serratus anterior Muscle
IV. Signs
- Serratus anterior weakness (Long Thoracic Nerve Palsy)
- Medial Scapula Winging increased when arms forward flexed and pushing against the wall
- Overhead abduction reduced (last 30 degrees lost)
- Levator Scapulae and rhomboid Muscle Weakness (Cranial Nerve 11 palsy)
- Lateral Scapula Winging increased when arms abducted
- Trapezius Muscle Weakness (Dorsal Scapular Nerve Palsy)
- Lateral Scapula Winging increased when arms abducted (similar to Cranial Nerve 11 palsy)
- Shoulder Abduction above 90 degrees is difficult
- Affected Shoulder droops
V. Imaging
- Evaluate for alternative causes
VI. Diagnostics
- Consider Electromyogram
VII. Differential Diagnosis
- See Cervical Spine Injury
- See Shoulder Injury
VIII. Management
- Oral Analgesics as needed (e.g. NSAIDS)
- Relative rest of affected Shoulder
- Physical Therapy
IX. Prognosis
- Most patients recover within 2 years with physical therapy and without surgery
X. References
- Kuczynski (2023) Crit Dec Emerg Med 37(10): 12-3
- Didesch (2019) J Hand Surg Am 44(4):321-30 +PMID: 30292717 [PubMed]
- Gooding (2014) Shoulder Elbow 6(1):4-11 +PMID: 27582902 [PubMed]