Inferior rectus muscle
| Inferior rectus | |
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| Rectus muscles: 2 = superior, 3 = inferior, 4 = medial, 5 = lateral Oblique muscles: 6 = superior, 8 = inferior Other muscle: 9 = levator palpebrae superioris Other structures: 1 = Annulus of Zinn, 7 = Trochlea, 10 = Superior tarsus, 11 = Sclera, 12 = Optic nerve |
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| Sagittal section of right orbital cavity. | |
| Latin | musculus rectus inferior bulbi |
| Gray's | subject #227 1022 |
| Origin | annulus of Zinn at the orbital apex |
| Insertion | 6.5 mm inferior to the limbus |
| Artery | |
| Nerve | inferior branch of oculomotor nerve |
| Actions | depression and adduction |
The inferior rectus muscle is a muscle in the orbit.
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[edit] Actions
It depresses, adducts, and helps extort (rotate laterally) the eye.
The inferior rectus muscle is the only muscle that is capable of depressing the pupil when it is in a fully abducted position.[1]
[edit] Innervation
As with most of the muscles of the orbit, it is innervated by the oculomotor nerve (Cranial Nerve III).
[edit] Additional images
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Eye movement of lateral rectus muscle, superior view
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Eye movement of medial rectus muscle, superior view
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Eye movement of inferior rectus muscle, superior view
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Eye movement of superior rectus muscle, superior view
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Eye movement of superior oblique muscle, superior view
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Eye movement of inferior oblique muscle, superior view
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Anterior view
credit: Patrick J. Lynch
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Dissection showing origins of right ocular muscles, and nerves entering by the superior orbital fissure.
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The right eye in sagittal section, showing the fascia bulbi (semidiagrammatic).
[edit] References
- ^ "Eye Theory". Cim.ucdavis.edu. http://cim.ucdavis.edu/Eyes/eyeText.htm. Retrieved 2010-11-27.
[edit] External links
- LUC ir
- SUNY Figs 29:01-07
- inferior+rectus+muscle at eMedicine Dictionary
- lesson3 at The Anatomy Lesson by Wesley Norman (Georgetown University) (orbit5)
- Diagram at mun.ca
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