Abstract
In facial palsy, the function of the chorda tympani probably reflects the intracanalicular pressure of the Fallopian canal because the nerve fibers of the chorda tympani can withstand pressure better than the motor fibers of the facial nerve even when the intracanalicular pressure is increased. The intracanalicular pressure in the Fallopian canal is caused by nerve degeneration and swelling.
We transsected the facial nerves of guinea pigs and observed nerve degeneration and swelling. We found that the swelling of the nerve began about 8 hours after nerve transsection and continued for about 14 days and then decreased gradually. Therefore, we concluded that the salivary flow and salivary pH tests, which are the methods of testing the function of the chorda tympani, should be done between 8 hours and 14 days after the onset of facial palsy.
