A 45-year-old man presents with complete ophthalmoplegia, ptosis, and anaesthesia in the distribution of the ophthalmic division of the trigeminal nerve on one side, along with proptosis. Visual acuity, pupillary reactions, and fundus examination are entirely normal. The lesion is MOST likely located at the:
- A Orbital apex
- B Optic canal
- C Superior orbital fissure ✓
- D Cavernous sinus anterior segment only
Correct answer: C. Superior orbital fissure
Explanation
The superior orbital fissure transmits cranial nerves III, IV, VI, the ophthalmic division of V, and sympathetic fibres, so a lesion here causes painful ophthalmoplegia, ptosis, and sensory loss while sparing vision. The optic nerve travels through the separate optic canal, so visual acuity, colour vision, and the pupil remain normal unless the lesion extends to the orbital apex. Involvement of vision is precisely what separates orbital apex syndrome from superior orbital fissure syndrome.
Reference: Parsons' Diseases of the Eye, 22nd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.