Erb's and Klumpke's palsies:
- Occur from trauma, such as birth trauma from breech birth, high birth weight, or suction.
- Birth trauma more commonly causes an Erb's palsy than a Klumpke's palsy.
- In adults, these occur from most commonly from trauma, such as from breaking a fall.
- Erb's palsy produces a "waiter's tip" deficit, which pictorializes the arm being at the side and pronated – the hand ready to receive the tip!
- Klumpke's palsy produces claw hand wherein the metacarpalphalangeal joints extend and the proximal interphalangeal joints flex, like a claw – it affects both ulnar and distal median nerve musculature, so all fingers are affected!