The growth rate and size of the mastoid air cell system and mastoid bone: a review and reference.

This review suggests a reference to the postnatal growth of mastoid air cells and bone. Information was retrieved from studies having large consecutive age groups, in order to reveal a development pattern. Data regarding origin, gender, and antibiotic treatment was investigated as well. Most measurements were obtained by planimetry. Assessment of the various data sources suggested the antrum to be well developed at birth (1-1.5 cm2), the mastoid cells to be about 3.5-4 cm2 at 1 year, followed by a linear growth till the age of 6 (1-1.2 cm2/year), having a slower increment up to adult size at puberty (approximately 12 cm2). The mastoid bone expansion is about 0.6-0.9 cm/year in length and width and 0.4 cm/year in depth in the first year, followed by half that rate until the age of 6-7. At puberty there was a slower sprout reaching adult size. Different ethnic groups share similar mastoid aeration and bone growth patterns. There were no differences between mastoid aeration measured at the pre-antibiotic era and after its widespread use. In conclusion, there are three distinguishable phases of mastoid pneumatization from birth till reaching final size. Bone and air cell compartments share a similar growth pattern; bone expansion lags behind aeration. Antibiotic treatment for otitis may have no impact upon mastoid aeration.