What conditions result from an injury of a 34-year-old man in a bar fight suffers a knife wound that severs the abducens nerve proximal to its entrance into the orbit?

Internal strabismus (medial deviation).

The abducens nerve (cn vi) innervates the lateral rectus muscle, which abducts the eyeball. Alesion of the abducens nerve results in medial strabismus (medial deviation) and diplopia (double vision). Ptosis of the upper eyelid is caused by lesions of the oculomotor nerve or sympathetic nerve to the levator palpebrae superioris. Inability to dilate the pupil is caused by a lesion of the sympathetic nerve to the dilator pupillae. The external strabismus (lateral deviation) is caused by paralysis of the medial rectus muscle, which is innervated by the oculomotor nerve. The loss of visual accommodation is due to a lesion of parasympathetic nerve fibers to the ciliary muscle.