Each eye is moved by six muscles, controlled by three cranial nerves (III, IV and VI). When you look straight ahead, the 4 rectus muscles of each eye do most of the work of aligning your eyes. The oblique muscles come more into play on turning or tilting your head. Each eye sends itts own picture to the brain. The brain compares the images, and sends signals to the nerves controlling the extraocular muscles to coordinate the eyes and prevent double vision. Below, on the left is a right eye, and on the right the left eye. The hook in the superior oblique muscle is where it passes through a little pulley at the upper, inner margin of the bony orbit around your eye.