Sphincter pupillae

Latin synonym: Musculus sphincter pupillae
Synonym: Sphincter pupillae muscle
Related terms: Sphincter pupillae muscle

Nerve: Short ciliary nerves

Action: Constricts pupil

Antagonist: Iris dilator muscle

Description:
The circular muscular fibers of the iris form the Sphincter pupillae; they are arranged in a narrow band about 1 mm. in width which surrounds the margin of the pupil toward the posterior surface of the iris; those near the free margin are closely aggregated; those near the periphery of the band are somewhat separated and form incomplete circles.

References

Text by Antoine Micheau, MD - Copyright IMAIOS