There are two groups of muscles within the orbit: extrinsic muscles of eyeball (extra-ocular muscles) involved in movements of the eyeball or raising upper eyelids, and intrinsic muscles within the eyeball, which control the shape of the lens and size of the pupil.
The extrinsic muscles include the levator palpebrae superioris, superior rectus, inferior rectus, medial rectus, lateral rectus, superior oblique, and inferior oblique.