USMLE Q Bank Step 1- 199

A 32-year old diabetic woman delivered a large baby after difficult vaginal delivery. At labor, the head emerged first and then the shoulders were stuck behind the bony pelvis. The obstetrician had to use some tools and maneuvers to deliver the baby. The baby had a good cry and red pink color but his right arm was not moving. It was hanging on his side with medial rotation.

Which of these nerve roots are most likely affected?

A- C5 and C6

B–C6 and C7

C–C7 and C8

D–C8 and T1


Shoulder dystocia is a condition characterized by difficulty to deliver shoulder of the baby after delivery of the head. There are some maneuvers used by the obstetrician to deliver it safely. Some complications could happen during manual delivery of the shoulder. Brachial plexus injury, fetal hypoxia and even fetal death are complications of these maneuvers. This case presentation represents Erb’s palsy which caused by injury to C5 and C6.

The correct answer is A

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