Repeated USMLE Questions Step 1- 309

An Acrobat player fell from a height of about 30 feet on her back during her performance and sustained a serious injury. Her thoracic and abdominal muscles are completely paralyzed. She is still able to breathe as the diaphragm is not paralyzed by this injury.

What is the most likely level of her injury?

A-Second cervical

B-Seventh cervical

C-Fifth thoracic

D-First lumbar

E-Third lumbar

Answer



The diaphragm, which is innervated by the phrenic nerve, escaped this injury. The phrenic nerve is originated from C3-C5 nerve roots so; the level of injury should be under the level of C5. Injuries of or under the level of T5 would spare some of the thoracic muscles.

The correct answer is B


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