Pathognomic features of Maxillary sinusitis is -
Characteristic finding of maxillary sinusitis on Rhinoscopy is pus or mucopus in in the middle meatus.
Mucosa and turbinates may appear red and swollen.

Remember: Dental infections are an important source of maxillary sinusitis.
Mucopus in the middle meatus
Inferior turbinate hypertrophy
Purulent nasal discharge
Atrophic sinusitis