Expansion
Erb's palsy is C5 to C6 (upper trunk); Klumpke's palsy is C8 to T1 (lower trunk)
Mnemonic
Two postures, two levels:
- Erb’s palsy - upper trunk, C5 and C6. The arm hangs adducted and internally rotated with the forearm pronated: the waiter’s tip position
- Klumpke’s palsy - lower trunk, C8 and T1. The intrinsic hand muscles fail, giving a claw hand, and Horner’s syndrome may accompany it because T1 carries the sympathetic fibres
Erb is high and the arm is limp; Klumpke is low and the hand is clawed. Erb follows excessive traction increasing the neck-to-shoulder angle, as in shoulder dystocia; Klumpke follows traction on an abducted arm, as in a breech delivery or a fall catching a branch.
Expansion
Erb’s palsy, upper trunk (C5 to C6):
- Caused by excessive widening of the head-to-shoulder angle
- Arm hangs adducted, internally rotated, forearm pronated - the “waiter’s tip”
Klumpke’s palsy, lower trunk (C8 to T1):
- Caused by excessive abduction of the arm, for example grabbing something in a fall
- Loss of the intrinsic hand muscles gives a claw hand
- May be associated with Horner’s syndrome from T1 involvement