Review Question - QID 213752

A 70-year-old man presents to the emergency department after a motor vehicle collision. He was in the front seat as a restrained driver in a head-on collision. He states that he hit the back of his head on the head rest but denies loss of consciousness or any symptoms at the time of the accident. He was removed from the car by the fire department, a cervical collar was placed, and was transported to the hospital. On arrival, the patient states that he feels weak. He has a past medical history of diabetes and atrial fibrillation and is currently being treated for these conditions. His temperature is 98.9°F (37.2°C), blood pressure is 109/70 mmHg, pulse is 88/min and irregular, and respirations are 15/min. Neurologic exam is notable for 2/5 strength in his upper extremities and 4/5 strength in his lower extremities. The patient has reduced temperature sensation in his upper extremities with normal sensation in his lower extremities. A postvoid residual volume is 772 mL. Which of the following is the most likely diagnosis?