Final answer:
In a right CN3 palsy, the patient's right eye would typically be positioned downward and outward, they may exhibit ptosis, experience diplopia, and have a dilated and non-responsive pupil.
Step-by-step explanation:
When a patient with a right CN3 palsy, also known as an oculomotor nerve palsy, is asked to look straight ahead, their right eye would typically be 'down and out,' which means it would be positioned downward and outward. This occurs due to the unopposed action of the lateral rectus and superior oblique muscles, which are innervated by the abducens nerve (CN6) and trochlear nerve (CN4) respectively, since CN3 innervates most other extraocular muscles such as the medial rectus, superior rectus, inferior rectus, and inferior oblique, which cannot function properly in CN3 palsy.
Additionally, the patient may have ptosis (drooping of the eyelid), as the levator palpebrae superioris muscle is also innervated by CN3. They may also experience diplopia (double vision) when looking straight ahead because of the misalignment of the eyes, and their pupil may be dilated and non-responsive to light due to impaired parasympathetic fibers running along CN3 that normally constrict the pupil.