A radiographic planimetric study of mastoid air cell system was carried out on 100 normal human subjects of which 50 were males and 50 females–who were further subdivided into five age groups. They had no history of past ear disease or any other clinical ENT abnormality. The mean area of the mastoid air cell system was measured planimetrically on X-rays and the data analysed according to age and sex. It was 12.05±0.67 cm2 in males and 11.45±0.70 cm2 in females (which are more or less the same as that of Western people).
The size of the cranial bones has no apparent role in the size variation of the mastoid air cell system. The development of the latter was very rapid up to 10 years of age in both sexes and it continued even after 20 years of age but at a much slower rate.