Erb’s Palsy & Klumpke’s Palsy

These are brachial plexus injuries seen most commonly in neonates after traumatic delivery, especially shoulder dystocia. They can also occur in adults after trauma.

Erb’s Palsy ("Waiter's Tip" Deformity)

• Newborn with shoulder dystocia
• Unable to abduct or flex the arm

Pathophysiology

• Injury to: Upper trunk of brachial plexus (C5-C6)
  • Musculocutaneous
  • Suprascapular
  • Axillary
• Caused by: Lateral traction on neck during delivery (e.g., shoulder dystocia), or trauma in adults (e.g., fall on shoulder)

Clinical Presentation

• Arm is:
  • Adducted (deltoid/supraspinatus weakness)
  • Internally rotated (infraspinatus weakness)
  • Extended at the elbow (biceps weakness)
  • Pronated (biceps/supinator weakness)
• "Waiter's tip" posture
• Reflexes: ↓ biceps reflex

Klumpke’s Palsy ("Claw Hand")

Pathophysiology

• Injury to: Lower trunk of brachial plexus (C8-T1)
  • Ulnar
  • Median (partially)
• Caused by:
  • Excessive upward traction on the arm during delivery
  • Adult trauma: grabbing a tree branch when falling

Clinical Presentation

• Claw hand:
  • Hyperextension at MCPs
  • Flexion at IPs
  • More pronounced in the 4th and 5th digits
• Sensory loss: medial arm/hand (ulnar distribution)
• Possible Horner syndrome if sympathetic fibers at T1 are involved (ptosis, miosis, anhidrosis)