Bony dehiscence between singular canal and round window niche.

Abstract

The incidence of bony dehiscence of the human singular canal was studied by examining 409 human temporal bones obtained from 300 individuals. Such a dehiscence was noted in three (0.7%) of the bones from three (1%) of the individuals, all male, aged 2, 6, and 76 years. All of these bony dehiscences were located between the round window niche and the cribrose area of the singular canal. The finding of a microfissure in the vicinity of the bony dehiscence in two of the three cases indicates that such dehiscences occur independently of microfissures. Although the incidence of bony dehiscences of the singular canal is small, these dehiscences appear to have considerable clinical significance in that they form a communication between the middle and inner ears or possibly between the middle ear and the cerebrospinal fluid space.