dilator pupillae

dilator pupillae

a muscle of the iris of the eye that dilates the pupil. It is composed of radial fibers, like spokes of a wheel, that converge from the circumference of the iris toward the center and blend with fibers of the sphincter pupillae near the margin of the pupil. The dilator pupillae is innervated primarily by nerve fibers from the sympathetic system (T2 sympathetic chain ganglia) through axons along the ciliary arteries. Compare sphincter pupillae.
References in periodicals archive ?
Abnormalities in the sympathetic visual pathway; these can occur anywhere between the posterior hypothalamus and the dilator pupillae
Direct damage to the sphincter or dilator pupillae muscles resulting in immobility of the pupil due to trauma, surgery or ocular inflammation, for example, anterior uveitis resulting in abnormal pupil shape.
Sympathetic fibres travel via the nasociliary nerve and the long ciliary nerves until they reach the ciliary body and dilator pupillae muscle.