Exostosis due to repetitive exposure to cold water is common in which pa of the temporal bone

Exostoses are multiple and bilateral, often presenting as smooth, sessile, bony swellings in the deeper pa of the meatus near the tympanic membrane. Outer 1/3rd pa of the external auditory meatus is formed by cailage and inner 2/3rd pa is formed by the temporal bone. It is often seen in persons exposed to the entry of cold water in the meatus as in divers and swimmers. (Ref: Diseases of ear, nose and throat, PL Dhingra, 7th edition, pg no. 118, 119)