Key points
  1. Accessory maxillary sinus ostia in superior meatus is a novel anatomical variation and were detected in 41.5% of patients.
  2. Among patients with accessary maxillary sinus ostia in superior meatus, two-thirds were found to be bilateral.
  3. Patients with accessory maxillary sinus ostia in superior meatus had significant lower Lund-Mackay score which represent less severity of rhinosinusitis.