Membrane Mucous Sinus Sphenoid Sphenoid Sinus Mucous Membrane Thickening Thickening Sphenoid Sinus Mucous Membrane Thickening YolondahtyuiStachtyu Saturday, April 15, 2017 What does maxillary sinus mucosal thickening mean? Webmd. To position it really, it means in your sinuses, you've got snot,that is mucus...