Objective: To investigate the location of the scala media in relation to the round window niche in human temporal bones.
Design: Ten human temporal bones were investigated by radical mastoidectomy and promontory drill-out.
Setting: Temporal bone laboratory.
Outcome measures: The distance from the scala media to the anterior edge of the round window niche, measured by Fisch's stapedectomy measuring cylinders.
Results: The scala media was identified at the transection point of a vertical line 1.6 to 2.2 mm (mean=1.8 mm; standard deviation=0.2) anterior to the anterior edge of the round window niche and a horizontal line 0.2 mm inferior to the lower border of the oval window.
Conclusion: This report demonstrates the point of entry into the scala media via the promontory in fixed temporal bone models, which may provide a site of entry for stem cells and gene therapy insertion.