Evaluation of the human petrotympanic fissure using anatomized cadaveric specimens and multi-detector CT imaging

Purpose The purpose of the current study is twofold. First, to investigate the variability of the petrotympanic fissure’s (PTF) morphology in anatomized human cadaveric specimens using multi-detector computed tomography (MDCT), and second, to compare the resulting measurements to investigate the possibilities of applying MDCT in the determination of PTF morphology in living humans. Methods Specimens ( n = 15) containing the temporal bone and TMJ were obtained from embalmed adult female (53.3%) and male (46.7%) cadavers and imaged using a helical 16-row scanner. Afterwards, cryosections were obtained and morphometric parameters were measured. Degree of agreement between both determinations was investigated and morphometric variables were also compared between PTF types. Results Three different types of PTF were identified. Type 1 was a wide tunnel-shaped structure. It was found in 20% of the cases. Type 2 was wide in the entrance but gradually narrows to the tympanic cavity. It was found in 46.7% of specimens. Finally, type 3, which was observed in 33.3% of the cases, was wide at the entrance of the mandibular fossa, followed by a middle region with flat-shaped tunnel structure and a narrow exit. The PTF’s vertical diameters at the mandibular fossa, midpoint, and tympanic cavity and the width at the mandibular fossa all were significantly greater in type 1 specimens. Conclusions MDCT is suitable for investigating the variable morphology of human PTF and its association with middle ear’s and TMJ pathologies.