dilator pupillae


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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 ?
Sympathetic fibres travel via the nasociliary nerve and the long ciliary nerves until they reach the ciliary body and dilator pupillae muscle.
The researchers suggest that the underlying reason for the improved accommodation ability in the test subjects may be due to the positively activated functions of three muscles in the eye; the constrictor pupillae muscle and dilator pupillae muscle working in coordination with the ciliary muscle.
Abnormalities in the sympathetic visual pathway; these can occur anywhere between the posterior hypothalamus and the dilator pupillae