High-resolution x-ray CT scanning of the human stapes footplate

Objectives: The mechanical behaviour of the footplate and its annular ligament depends critically on their shape and orientation in the oval window, but accurate measurements have been difficult to make due to their small size. Our aims are to visualize the footplate at high resolution and understand its dynamics. Methods: The human cadaver stapes footplate was dissected and very high resolution x-ray CT scans, with voxel sizes from 4 to 8 μm, were performed. Locally developed software was used to reconstruct the images. Results: The data permit us to explore minor details of shape and orientation. The footplate looks like a footprint, and the annular ligament has variable thickness with a cleft ( groove ) in its anterior attachment to the oval window. The CT data also permit us to create a 3-D finite-element model which can simulate footplate motion. Conclusions: The results obtained lead to further understanding of the mechanical behaviour of the footplate and the annular ligament. Author