Inferior oblique muscle

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Inferior oblique
Eyemuscles.png
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 obliquus inferior bulbi
Gray's subject #227 1023
Origin: orbital surface of the maxilla, lateral to the lacrimal groove
Insertion: laterally onto the eyeball, deep to the lateral rectus, by a short flat tendon
Artery:
Nerve: oculomotor nerve
Action: extorsion, elevation, abduction
Dorlands/Elsevier m_22/12549875

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]


The Obliquus oculi inferior (inferior oblique) is a thin, narrow muscle, placed near the anterior margin of the floor of the orbit.

Action

Its actions are lateral rotation, elevation and abduction of the eye.

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.

Path

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).

Innervation

The inferior oblique is innervated by the inferior division of the oculomotor nerve (cranial nerve III).

Clinical significance

While commonly affected by palsies of the inferior division of the oculomotor 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".

  • Kushner BJ (2006). "Multiple mechanisms of extraocular muscle 'overaction'". Arch Ophthalmol. 124 (5): 680–8. PMID 16682590. 

Surgical procedures of the inferior oblique include: loosening (recession), myectomy, marginal myotomy, and denervation and extirpation.

Additional images

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.

de:Augenmuskeln#Musculus_obliquus_inferior hu:Musculus obliquus inferior bulbi nl:Musculus obliquus inferior



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