1) Air cavities in the head 2) Allergies may congest them 3) Allergies often affect them 4) Cold victims 5) Commonly congested cavities 6) Congestion sites 7) Head cavities 8) Holes in the head 9) Holes in your head 10) Nasal bone cavities 11) Nasal spray targets 12) Sites of congestion 13) They may be blocked 1) Antra 2) Iters 
• (pl. ) of Sinus
Air filled cavities in our skulls above our upper teeth, between the eyes, and between the eyebrows. Sinus infections are a common source of facial pain and headaches that can be confused with dental pain from upper back teeth.
Air filled cavities. ... Examples are the ethmoids, maxillary, frontal and sphenoid sinuses. ... (27 Sep 1997) ... 
Air spaces within the skull that are in contact with ambient pressure through openings in the back of the nasal passages.