Eng and Chang were conjoined twins who were born in Thailand and settled in the United States at the age of 18 years. Numerous surgeons in the United States and Europe examined them and almost all of them believed that an attempt at separation would be fatal. They married sisters and lived on a farm in North Carolina where they loved to hunt wild game. Both used shotguns placed on their right shoulders. At the age of 58 years, it was noted that Chang, who was located to the left of Eng, had a hearing loss in both ears and that Eng had a loss that was greater in the left ear. It is proposed that these hearing losses may have been caused by muzzle-blast injury from hunting and that only the right ear of Eng was privileged to experience the protective effect of head shadow.