Paranasal sinus opening in middle meatus:
Anterior group of paranasal sinus which includes maxillary, frontal and anterior ethmoidal. They all open in the middle meatus and their ostia lie anterior to basal lamella of middle turbinate Ref: Dhingra 7e pg 209.
maxillary
Anterior ethmoid
Posterior ethmoid
Frontal
Nose and paranasal sinuses