A radiologico-anatomical comparative study of the cochlear aqueduct

AIM: A comparative radiologico-anatomical study of the cochlear aqueduct (C A) was performed. MATERIALS AND METHODS: Eight cadavers and 23 dry temporal bones were studie d. High-resolution computed tomography (HRCT) was carried out on each cadav er before microdissection. Microdissection was carried out in a plane paral lel to the HRCT sections. RESULTS: The CA was found to be located an average of 7 mm inferior to the internal acoustic meatus and at the superior edge of the jugular foramen. T he external aperture of the CA was triangular in shape in 18 bones (78.3%). The petrosal fossa was located just inferior to the external aperture and housed the glossopharyngeal nerve, which had an incomplete bony canal in fo ur bones (17.4%) and a complete bony canal in three bones (13%). It was pos sible to demonstrate the petrosal portion of the CA on both coronal and axi al HRCT. The otic capsule segment of the CA was impossible to demonstrate o n coronal sections. CONCLUSION: The CA cannot be visualized in only one section of the plane in HRCT. Both the otic capsule and petrosal segments can be demonstrated on a xial HRCT. (C) 2000 The Royal College of Radiologists.