A 73-year-old man slipped in the bathroom, falling, and striking his forehead on the toilet. In the emergency room he complains of neck pain and subjective weakness of his upper extremities. Examination reveals 3/5 strength to elbow flexion, elbow extension, and grip. Examination of his lower extremity shows he is able to straight leg raise against gravity bilaterally, with 4+/5 strength to knee extension bilaterally. The patient reports prior to the fall he was active, playing doubles tennis, and had no problems with dexterity in his hands. Figure A is the sagittal MRI of the cervical spine. What is the likely pathogenesis for the patient's symptoms?