Distribution of the fungiform papillae after transectioning the chorda tympani nerve

Abstract

Taste disorders often occur following transection of the chorda tympani nerve (CTN) during middle ear surgery. It has been shown that the severeness of taste disorders and the recovery period varied in each case. In this paper, we observed the distribution of the fungiform papillae (FPs) of the tongue macroscopically following tran section of the CTN. Fifteen ears of 15 patients (8 men and 7 women) were subjected to this study. The distribution of FPs in the apex liguaes was classified as follows. A: FPs which were located in the operative side atrophied and disappeared (n=2). B: FPs were found in the operated side within 1cm over the midline of the tongue (n=3). C: FPs were found in the operated side more than over 2cm from the midline (n=2). However FPs at the corpus linguaes were never found in the operative side over the midline of the tongue (n=7). These findings indicate that not only the apex liguaes but also the corpus linguaes may have innervation crossover or reinnervation, and that the reinnervatioin can extend more than over 2cm beyond the midline of the tongue.