The sinuses are cavities or air-filled pockets near the nasal
passage. Like the nasal passage, the sinuses are lined with
mucous membranes. There are four different types of sinuses:
ethmoid sinus: located inside the face, around the area of the
bridge of the nose. This sinus is present at birth and continues
to grow. maxillary sinus: located inside the face, around the
area of the cheeks. This sinus is also present at birth and
continues to grow. frontal sinus: located inside the face, in
the area of the forehead. This sinus does not develop until a
child is around 7 years old. sphenoid sinus: located deep in the
face, behind the nose. This sinus does not develop until
adolescence. What is sinusitis? acute sinusitis: occurs quickly
and improves with the appropriate treatment subacute sinusitis:
does not improve with treatment initially, and lasts less than
three months - chronic sinusitis: occurs with repeated acute
infections or with previous infections that were inadequately
treated, and lasts longer than