It is estimated that 7 striated outer eye muscles connected to each eye. Of these, 6 attach to the actual eyeball (1 - 6 below) and one (7 below) to the upper eyelid.
1/ The internal straight eye muscle (musculus rectus medialis).
2/ The lower straight eye muscle (musculus rectus inferior).
3/ The upper straight eye muscle (musculus rectus superior).
4/ The lower oblique eye muscle (musculus obliquus inferior).
5/ The upper oblique eye muscle (musculus obliquus superior)
6/ The outer straight eye muscle (musculus rectus lateralis)
7/ The eyelid lifter muscle (musculus levator palpebrae superioris) lifts the upper eyelid.
The muscles no.1 to no.4 and no.7 are innervated/supplied by cranial nerve III (nervus oculomotorius).
Muscle no.5 is innervated/supplied by cranial nerve IV (nervus trochlearis)
Muscle no. 6 is innervated/supplied by cranial nerve VI (nervus abducens)
Under normal conditions, the two eyes interact with each other and perform so-called conjugate movements. Coordination must be exat!! If not, double vision occurs - the main sign that an eye muscle or its nerve supply is damaged.
The balanced activity of the eye muscles, current gaze direction setting and the conjugated movement patterns of the eyes are controlled by an extremely complex system of interacting gaze direction centers