Lesion of the marked structure affects all EXCEPT (AIIMS May 2019)
(A) Superior rectus (B) Superior oblique (C) Inferior oblique (D) Medial rectus
(B) Nerve pointed in diagram is oculomotor nerve (cranial nerve III) Extrinsic muscles of the eyeball are innervated by 3 cranial nerves. 3 | lateral rectus innervated by 6th cranial nerve Superior oblique by 4th cranial nerve Remaining muscles by 3rd cranial nerve. Among these 3 cranial nerves, oculomotor nerve is most medial, trochlear is most lateral & abducens pierces dura mater b/w these two at base of cranial cavity. MUSCLE OF EYE ACTION SUPERIOR RECTUS ELEVATION, ADDUCTION, MEDIAL ROTATION OF EYE BALL. LEVATOR PALPEBRAE SUPERIORIS ELEVATION OF UPPER EYELID MEDIAL RECTUS ADDUCTION OF EYEBALL. INFERIOR RECTUS DEPRESSION, ADDUCTION, LATERAL ROTATION OF EYEBALL. INFERIOR OBLIQUE ELEVATION, ABDUCTION, LATERAL ROTATION OF EYEBALL SUPERIOR OBLIQUE DEPRESSION, ABDUCTION, MEDIAL ROTATION OF EYEBALL CILIARIS AND SPHINCTER PUPILLAE CONSTRICTS CILIARY BODY & PUPIL