Iris sphincter muscle
| Iris sphincter muscle | |
|---|---|
Iris, front view. (Muscle visible but not labeled.) | |
The upper half of a sagittal section through the front of the eyeball. ("Sphincter of pupil" labeled near bottom-center.) | |
| Details | |
| Origin | Encircles iris |
| Insertion | Encircles iris |
| Artery | Long posterior ciliary arteries |
| Nerve | Short ciliary nerves |
| Actions | Constricts pupil |
| Antagonist | Iris dilator muscle |
| Identifiers | |
| Latin | musculus sphincter pupillae |
| TA98 | A15.2.03.029 |
| TA2 | 6762 |
| FMA | 49157 |
| Anatomical terms of muscle | |
The iris sphincter muscle (pupillary sphincter, pupillary constrictor, circular muscle of iris, circular fibers) is a muscle in the part of the eye called the iris. It encircles the pupil of the iris, appropriate to its function as a constrictor of the pupil.
The ciliary muscle, pupillary sphincter muscle and pupillary dilator muscle sometimes are called intrinsic ocular muscles or intraocular muscles.