Paranasal sinuses – normal maturation

Maxillary sinus
  • first to develop.
  • rudimentary at birth.
  • 2mm/year growth rate in vertical dimension
  • growth till end of puberty
  • 1 year: lateral margin of sinus projects under medial orbital wall.
  • 4 years: extends laterally past infraorbital canal.
  • 9 years: reaches maxillary bone and plane of hard palate
Ethmoid sinuses
  • at birth: developed anteriorly more than posteriorly.
  • lack of pneumatization of posterior ethmoids – normal till 6 years.
  •  eventually posterior ethmoid air cells larger and fewer than anterior.
  • last to develop – agger nasi, Haller and concha bullosa.
Sphenoid sinuses
  • soon after birth, begin to pneumatize; as early as 2 years.
  • pneumatization proceeds inferiorly, posteriorly and laterally.
  • first presphenoid, followed by basisphenoid, greater wings and pterygoid processes.
Frontal sinuses
  • last to develop.
  • extensions of anterior ethmoid air cells.
  • earliest at 2 years in the orbital processes of frontal bone
  • 4 years: nasion
  • 8 years: orbital roof.
  • 10 years: vertical portion of frontal bone.
  • growth till end of puberty.


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