A 30-year-old woman presents with sudden vertical diplopia after a fall. Examination shows a left hypertropia that worsens on right gaze and on left head tilt. She tilts her head to the right to eliminate the double vision. Which muscle is palsied?
- A Left superior oblique ✓
- B Right inferior oblique
- C Left superior rectus
- D Right medial rectus
Correct answer: A. Left superior oblique
Explanation
The three-step test identifies the paretic cyclovertical muscle. C left hypertropia means a weak depressor of the left eye or overacting elevator of the right. Hypertropia worsening on right gaze implicates the left superior oblique or left superior rectus. Worsening on ipsilateral (left) head tilt confirms the left superior oblique, because head tilt to the same side normally requires that muscle to intort against unopposed elevators. Head tilting away from the palsied side is the classic compensatory posture.
Reference: Parsons' Diseases of the Eye, 23rd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.