Sinusitis which is least involved is?
Sinusitis is least involved in the sphenoid sinus. Isolated involvement of this sinus is rare. It's often pa of pansinusitis or is associated with infection of posterior ethmoid sinuses. (Reference: Textbook of PL Dhingra and Shruti Dhingra; 7th edition, pg no. 216)
Maxillary
Ethmoid
Frontal
Sphenoid
Nose and paranasal sinuses