Birth brachial plexus palsy vs Clavicular fracture pseudoparalysis
How to tell Birth brachial plexus palsy and Clavicular fracture pseudoparalysis apart when a board question makes them look alike.
Plexus palsy is neurologic weakness in a root pattern; clavicular fracture is painful pseudoparalysis with intact distal nerves.
Side by side
Birth brachial plexus palsy follows traction injury during delivery and produces neurologic weakness such as Erb C5-C6 waiters-tip posture or Klumpke C8-T1 claw hand with possible Horner syndrome.
Clavicular fracture pseudoparalysis causes decreased spontaneous arm movement because motion is painful, but grasp, reflexes, and distal neurologic function are preserved.
Traction stretches or tears brachial plexus roots/trunks, creating a neuroanatomic motor pattern.
A fractured clavicle causes pain-limited movement without primary nerve injury.
Brachial plexus palsy: asymmetric Moro, root-specific weakness, sensory/reflex pattern; Erb C5-C6 or Klumpke C8-T1 clues.
Clavicular fracture: crepitus or callus over clavicle, pain with passive movement, intact grasp and distal neurologic exam, fracture on radiograph.
The trap
Erb is C5-C6 waiter tip; Klumpke is C8-T1 claw hand.
The repair move
Before naming the answer, force the stem through the separator: Erb is C5-C6 waiter tip; Klumpke is C8-T1 claw hand.
Try a free question
CoreA newborn delivered with shoulder dystocia has a flaccid right arm. The arm hangs limp with extended elbow, internally rotated shoulder, pronated forearm, and flexed wrist ('waiter's tip posture'). Moro reflex is absent on the right but intact on the left. Grasp reflex is INTACT on both sides. Which condition is most likely?
Show answer and explanation
Answer: A. BIRTH BRACHIAL PLEXUS PALSY. Birth brachial plexus palsy occurs with shoulder dystocia or excessive lateral neck traction during delivery. Upper trunk (Erb-Duchenne) palsy is most common (C5-C6 injury), producing waiter's tip posture: extended elbow, internally rotated shoulder, pronated forearm, flexed wrist. Moro absent (loss of shoulder abduction); grasp INTACT (C8-T1 ulnar/median nerves spared). Lower trunk (Klumpke) palsy (C8-T1) has claw hand and possible Horner syndrome.
Why the other choices are tempting
- B. Clavicular fracture pseudoparalysis has intact grasp and intact distal neurologic exam; pain limits movement but no nerve injury.
- C. Cerebral palsy is later-onset upper motor neuron picture.
- D. Spinal cord injury would be bilateral and have sensory level.
- E. Congenital muscular torticollis is sternocleidomastoid contracture, not arm weakness.
Flashcards
Tap a card to flip it.
What clue supports Erb birth palsy?
Choose Erb birth palsy when the stem gives this pattern: Erb palsy is upper brachial plexus C5-C6 injury from shoulder dystocia, causing waiter tip posture.
What clue supports Klumpke birth palsy?
Choose Klumpke birth palsy when the stem gives this contrasting pattern: Klumpke palsy is lower brachial plexus C8-T1 injury, causing claw hand and possible Horner syndrome.
Quick answers
What is the fastest way to tell Birth brachial plexus palsy from Clavicular fracture pseudoparalysis?
Plexus palsy is neurologic weakness in a root pattern; clavicular fracture is painful pseudoparalysis with intact distal nerves.
What is the key clue for Birth brachial plexus palsy?
Birth brachial plexus palsy follows traction injury during delivery and produces neurologic weakness such as Erb C5-C6 waiters-tip posture or Klumpke C8-T1 claw hand with possible Horner syndrome.
What is the key clue for Clavicular fracture pseudoparalysis?
Clavicular fracture pseudoparalysis causes decreased spontaneous arm movement because motion is painful, but grasp, reflexes, and distal neurologic function are preserved.
What is the common trap with Birth brachial plexus palsy vs Clavicular fracture pseudoparalysis?
Erb is C5-C6 waiter tip; Klumpke is C8-T1 claw hand.