Extrinsic Eye Muscles

The upper eyelid is more movable than the lower eyelid. The upper eyelid is elevated by the superior levator palpebrae muscle.

On the superior aspect of the orbit of the eye is the superior rectus muscle. On the inferior aspect of the orbit of the eye is the inferior rectus muscle. These two muscles move the eye straight up and down.

On the lateral aspect of the orbit of the eye is the lateral rectus muscle. On the medial aspect of the orbit of the eye is the medial rectus muscle. These two muscles move the eye from side to side.

Between the medial rectus muscle and the superior rectus muscle is the superior oblique muscle. This muscle passes through a cartilaginous loop, the trochlea, to attach to the eyeball. Antagonist to the superior oblique muscle is the inferior oblique muscle. These two muscles cause the eye to move at angles.

Images Extrensic Eye Muscles
Figure 24.3 Extrinsic Eye Muscles, Superior View

Inferior oblique Inferior rectus Lateral rectus Medial rectus Optic nerve II Superior oblique Superior rectus Trochlea

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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