The nerve innervating the pupil opening muscle is the sympathetic nerve.
The pupil opening muscle is located within the iris tissue and is innervated by sympathetic nerve fibers that, when excited, cause the pupil to open wide, thus allowing more light to enter the interior of the eye and therefore facilitating the patient’s ability to see in dimly lit environments.
Sympathetic nerve fibers emanate from the cranium and enter the interior of the orbit, where they send postganglionic nerve fibers after the ciliary ganglion commutation to enter the interior of the eye and reach the iris tissue, thereby innervating the pupil-opening muscles.
Once the patient suffers from eye trauma or hematoma or inflammation in the orbit, it can affect the function of sympathetic nerve fibers, which can cause the function of pupil opening muscle to be impaired, thus showing abnormal pupil size.
It is recommended that patients with abnormal pupil size should consult a doctor in time to evaluate their condition and follow the doctor’s instructions for treatment.