A 24 year old man on physical examination was noted to have ptosis. Which of the following muscle must be paralyzed?
High-Yield Explanation
The superior tarsal muscle is a smooth muscle which is sympathetically innervated. It is an involuntary muscle that elevates the eyelid. It is innervated by the cervical sympathetic trunk, and this muscle's functioning provides a good indication of the integrity of the cervical sympathetic trunk. If the cervical sympathetic trunk has been damaged, a patient will have ptosis, a droopy eyelid.