Which nerve is evaluated through extraocular movements in cases of orbital fracture?

In evaluating extraocular movements in cases of orbital fracture, the correct focus is on the oculomotor nerve. This nerve is responsible for the movement of most extraocular muscles, which control eye movement, as well as for the eye’s ability to accommodate for near vision and to constrict the pupil. If there is an orbital fracture, particularly affecting the inferior rectus muscle or the muscles of the eye that the oculomotor nerve innervates, this can lead to limitations in eye movement or diplopia (double vision).

Other nerves mentioned, such as the optic nerve, infraorbital nerve, and nasociliary nerve, have different functions. The optic nerve primarily carries visual information from the retina to the brain, while the infraorbital nerve supplies sensation to the lower eyelid, cheek, and upper lip. The nasociliary nerve contributes to sensory innervation of the nasal cavity and portions of the eye but does not play a direct role in eye movement. Therefore, the assessment of eye movement and any resulting dysfunction in cases of orbital fractures primarily tests the integrity of the oculomotor nerve.