<prompt> Person is not able look down. Which extra ocular muscle is affected:Superior obliqueInferior obliqueSuperior rectusLateral rectus  <response>: Ans. a Superior obliqueRef: A.K. Khurana 6th ed. 337-39 The function of superior oblique is quite contrary to its name. Its action is depression of eyeball, which helps to see down. Its yoke muscle is inferior rectus, which also has the similar function as superior oblique. There are 9 Gaze: Primary : Straight Secondary: Up, down, left, right Tertiary: Up left, Up, right, Down left, Down right ACTIONS OF EOMMuscleFunction PrimarySecondaryTertiaryLateral rectusAbduction--Medial RectusAdduction--Inferior RectusDepressionExtortionAdductionSuperior rectusElevationIntortionAdductionInferior ObliqueExtortionElevationAbductionSuperior obliqueIntortionDepressionAbduction Mnemonics: SinRad all superior muscles causes Intortion; all rectus muscles causes Adduction EXCEPT Lateral rectus 