Spieren van het oog

Each eye has six extraocular muscles, three involuntary intraocular muscles, and one primary eyelid retractor muscle.

Four extraocular muscles— the superior, inferior, lateral, and medial recti—originate on a common tendinous ring that encloses the optic foramen and insert on the sclera.

The superior oblique muscle originates above the optic foramen, while the inferior oblique muscle originates on the maxilla below the orbit. Both these muscles insert laterally on the sclera.

Together, these six muscles coordinate up, down, sideways, and diagonal eyeball movements.

Additionally, the levator palpebrae superioris, with its origin in the wing of the sphenoid bone and insertion on the upper eyelid, acts as the primary retractor of the eyelid, allowing eye-opening motion.

It is an antagonist to the facial muscle, orbicularis oculi, which facilitates eyelid closure or protraction.

The three intraocular smooth muscles comprise the ciliary muscle, dilator pupillae, and sphincter pupillae.

These muscles control the lens and pupil movements to change the focal length of the eye for accommodation of vision.