Erb's Palsy
When shoulder dystocia occurs during the birth, injury to the brachial plexus can occur. This photo shows how the posture of the arms is asymmetric: the left arm is at the side and the hand is medially rotated at a time when the other arm is flexed with crying. Testing the Moro (startle) reflex in this infant produces a similar result as the left arm does not raise as high as the right. Most brachial plexus injuries of this type resolve spontaneously. Improvement in movement can often be noted within the first 24 hours. If improvement does not occur, referral to a pediatric neurologist, and possibly a physical therapist, is warranted.
photo by Janelle Aby, MD