Inferior oblique muscle
From Wikipedia, the free encyclopedia
| Inferior oblique | ||
|---|---|---|
| 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 | ||
| Sagittal section of right orbital cavity. | ||
| Latin | Obliquus oculi inferior | |
| Gray's | subject #227 1023 | |
| Origin: | inferior rim of the orbit, directly below the supraorbital notch | |
| Insertion: | laterally onto the eyeball, deep to the lateral rectus, by a short flat tendon | |
| Blood: | ||
| Nerve: | oculomotor nerve | |
| Action: | Primary action is extorsion; secondary action is elevation; tertiary action is abduction (i.e. it extorts the eye and moves it upward and outward). The field of maximal inferior oblique elevation is in the adducted position. | |
The Obliquus oculi inferior (inferior oblique) is a thin, narrow muscle, placed near the anterior margin of the floor of the orbit.
Its actions are lateral rotation, elevation and abduction of the eye.
It arises from the orbital surface of the maxilla, lateral to the lacrimal groove.
Passing lateralward, backward, and upward, between the inferior rectus and the floor of the orbit, the inferior oblique inserts onto the scleral surface between the inferior rectus and lateral rectus.
It is the only muscle of eye movement whose origin is not on the common tendonous ring (annulus of Zinn).
The inferior oblique is innervated by the inferior division of the oculomotor nerve (cranial nerve III). While commonly affected by palsies of this nerve, isolated palsies of the inferior oblique (without affecting other functions of the oculomotor nerve) are quite rare.
"Overaction" of the inferior oblique muscle is a commonly observed component of childhood strabismus, particularly infantile esotropia and exotropia. Because true hyperinnervation is not usually present, this phenomenon is better termed "elevation in adduction".
Surgical procedures of the inferior oblique include: loosening (recession), myectomy, marginal myotomy, and denervation and extirpation.
[edit] External links
This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.
 | This eye article is a stub. You can help Wikipedia by expanding it. |
