From the Research
Mastoids begin to form during fetal development but are not fully developed at birth, with significant development occurring during the first two years of life and continued growth and pneumatization throughout childhood, typically reaching adult form by adolescence, around 12-15 years of age, as supported by the most recent study 1. The mastoid process, which is a bony prominence located behind the ear, starts as a flat area in newborns and gradually pneumatizes (develops air cells) during childhood. Key points about mastoid development include:
- The antrum is well developed at birth, with a size of around 1-1.5 cm2, as reported in 2.
- The mastoid cells are about 3.5-4 cm2 at 1 year, followed by a linear growth till the age of 6, with a growth rate of 1-1.2 cm2/year, as found in 2.
- 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, as measured in 2.
- Different ethnic groups share similar mastoid aeration and bone growth patterns, as noted in 2.
- The size of mastoid air cells with respect to age differs among populations of different origins, with the highest growth rate reported up to 30 years, as shown in 1.
- Sex also influences the size of mastoid air cells and growth rate with age, with females having larger air cells with rapid growth until puberty, while males continue a steady growth after puberty and become larger, as reported in 1.