<prompt>  A 24 year old man falls on the ground when he is struck in the right temple by a baseball. While being driven to the hospital, he lapses into coma. He is unresponsive with the dilated right pupil when he reaches the emergency department. The most important step in initial management is -CraniotomyCT scan of the headX-ray of the skull and cervical spineDoppler ultrasound examination of the neck 