A 62-year-old man is brought to the ED after sudden onset of dizziness and facial weakness. On exam, he has an inability to abduct the right eye on attempted rightward gaze and decreased movement of the right side of the face including the forehead. Corneal reflex is diminished on the right when the cornea is touched. Hearing is intact. CT head is negative for hemorrhage. MRI shows a small infarct in the dorsal brainstem at the level of a ventral bulge and a CSF-filled cavity posteriorly.

Which of the following best describes the anatomic relationship that explains why this lesion can produce both impaired eye abduction and ipsilateral facial weakness?