下斜筋 （ かしゃきん、 英 ： inferior oblique 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.
See also: Extraocular muscles
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.[1]
【 語 句 】
・ orbit ： 眼窩 ・ extraocular muscle ： 外眼筋 ・ maxillary bone ： 上顎骨 ・ oculomotor nerve ： 動眼神経 ・ lacrimal groove ： 涙嚢溝 ・ common tendinous ring ： 総腱輪 ・ scleral： 強膜の
【 Innervation 】
The inferior oblique is innervated by the inferior division of the oculomotor nerve (cranial nerve III).
See also: Eye movement
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.[2]
【 語 句 】
・ cranial nerve ： 脳神経 ・ extorsion ： 外旋 ・ abduction ： 外転 ・ tertiary ： 第3の ・ adducted ： 内転させられた
