It seems that there are few subjects in medicine that are as difficult to commit to memory as the eye movements.
Firstly the nerves: all the muscles are innervated by the third nerve except for LR6SO4 - a useful memory aid as it sounds like a chemical formula. Thus: Lateral Rectus - nerve VI, Superior Oblique - IV.
Therefore all movements of the eye are supplied by the IIIrd nerve, except for lateral movement - abduction - by the VIth nerve, and downward and inward movements by the IVth.
The rectus muscles move the eyes in the directions suggested by their names, since their insertion is uncomplicated. The vertical rectus muscles - superior and inferior - have an adducting component.
The oblique muscles move the eyes up and down in the adducted position, but in an opposite direction to that suggested by their names. Thus, superior oblique moves the adducted eye downwards.
Last reviewed 01/2018