You are called to a construction site where a 27-year-old worker has fallen from the second floor. He landed on his back and is drifting in and out of consciousness. A quick assessment reveals no bleeding or blood loss. His blood pressure is 90/60 mm Hg with a pulse rate of 110 beats/min. His airway is open and breathing is within normal limits. You realize the patient is in shock. The patient's shock is due to an injury to the:
[1] cervical vertebrae.
[2] skull.
[3] spinal cord.
[4] peripheral nerves.
