Makindo Medical Notes

Erb’s palsy most commonly occurs after shoulder dystocia during vaginal delivery. Forced depression of the shoulder stretches the upper brachial plexus (C5–C6), producing marked weakness of the deltoid, biceps, and proximal arm muscles.

📖 About

• Injury to the upper roots of the brachial plexus (C5–C6).
• Classically occurs when the head is forcibly separated from the ipsilateral shoulder.

🧬 Aetiology

• Birth trauma (shoulder dystocia → traction injury to C5/C6).
• Direct trauma (falls, penetrating injury – knife or gunshot).
• Stretching or rupture of the upper roots of the brachial plexus.

🩺 Clinical Features

• Classic posture: “waiter’s tip” (or “bellboy’s tip”) position.
• Weakness/paralysis of:
  • Shoulder abductors (deltoid, supraspinatus).
  • Elbow flexors (biceps, brachialis, coracobrachialis).
  • Forearm supinators (biceps) → arm rests pronated.
• Sensory loss: lateral aspect of the upper arm (deltoid region).
• Distal strength (hand and fingers) usually preserved.

🧷 Associated Injuries

• Fractured clavicle or humerus.
• Shoulder dislocation or cervical spine injury.
• Cervical cord injury or facial palsy in severe cases.
• Occasionally: Horner’s syndrome if lower plexus also involved.
• In neonates: phrenic nerve palsy → diaphragmatic paralysis requiring respiratory support.

🔍 Differentials

• Brain injury or cerebral palsy (especially in neonates).
• Isolated radial or axillary nerve injury.

🧪 Investigations

• Plain radiographs to exclude fractures.
• Electromyography (EMG) and nerve conduction studies (help assess prognosis).
• MRI of the brachial plexus in severe or persistent cases.

💊 Management

• Immobilise the affected arm across the abdomen for 7–10 days if painful.
• Early passive physiotherapy to maintain range of motion.
• Most neonatal cases improve spontaneously over weeks to months.
• Persistent or severe injuries may require surgery:
  • Nerve transfers (from contralateral limb).
  • Subscapularis release.
  • Latissimus dorsi tendon transfer to restore function.

📚 References

• Royal College of Paediatrics and Child Health – Neonatal Brachial Plexus Injury guidance.
• Oxford Handbook of Orthopaedics and Trauma.
• NCBI StatPearls – Erb Palsy