anatomy of the sinuses
Last reviewed 01/2018
The sinuses are paired cavities within the facial bones which are lined with respiratory epithelium.
The sinuses do not develop together. At birth, only the ethmoids are well developed and these may occupy up to 50% of the face. The frontals usually pneumatise after 7 years of age, but don't always develop. The maxillary sinuses develop with the second teeth.
The arrangement means that sinusitis in childhood, essentially, is ethmoiditis.