Inferior oblique muscle

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.
Details
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	ophthalmic artery
Nerve	oculomotor nerve
Actions	extorsion, elevation, abduction
Identifiers
Latin	musculus obliquus inferior bulbi
Dorlands /Elsevier	m_22/12549875
TA	A15.2.07.019
FMA	49040
Anatomical terms of muscle []

The inferior oblique muscle or obliquus oculi inferior is a thin, narrow muscle placed near the anterior margin of the floor of the orbit. The inferior oblique is an extraocular muscle, and is attached to the maxillary bone (origin) and the posterior, inferior, lateral surface of the eye (insertion). The inferior oblique is innervated by the inferior branch of the oculomotor nerve.

The inferior oblique arises from the orbital surface of the maxilla, lateral to the lacrimal groove. Unlike the other extraocular muscles (recti and superior oblique), the inferior oblique muscle does not originate from the common tendinous ring (annulus of Zinn).

Passing lateralward, backward, and upward, between the inferior rectus and the floor of the orbit, and just underneath the lateral rectus muscle, the inferior oblique inserts onto the scleral surface between the inferior rectus and lateral rectus.

In humans, the muscle is about 35 mm long.

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

Its actions are extorsion, elevation and abduction of the eye.

Primary action is extorsion (external rotation); secondary action is elevation; tertiary action is abduction (i.e. it extorts the eye and moves it upward and outwards). The field of maximal inferior oblique elevation is in the adducted position.

The inferior oblique muscle is the only muscle that is capable of elevating the eye when it is in a fully adducted position.