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)