Common confusion Subject:- Neuro Ophthalmology SIN (S IN = Superior Oblique Intorsion) The Superior Oblique (SO) muscle primarily causes intorsion of the eye. RAD (R AD = Recti Adduction) The Rectus muscles (medial and lateral recti) are primarily involved in adduction and abduction of the eye. Medial rectus: Adduction (moves the eye inward). Lateral rectus: Abduction (moves the eye outward). Recti muscles do the opposite action of their anatomical names in vertical gaze. Oblique muscles act in the same direction as their anatomical names in vertical gaze. "Recti Opposite, Obliques Same" Now This one :- Rectus Muscles (Opposite Actions): Superior Rectus (SR): Elevates the eye but primarily in abduction. Inferior Rectus (IR): Depresses the eye but primarily in abduction. Oblique Muscles (Same Direction): Superior Oblique (SO): Depresses the eye (in adduction). Inferior Oblique (IO): Elevates the eye (in adduction).