Fig. 3. Mid-sagittal anatomy of buccal mass and radular stalk measurements. Key anatomical features visible in mid-sagittal fixed tissue (A) and in high-spatial-resolution magnetic resonance (MR) images (B) are indicated. The features outlined in the high-temporal-resolution MR images (see Fig. 4) are visible. To create a reference length for measurements that could be reliably measured on the high-temporal-resolution MR images, the length of the inner width of the radular stalk was used. To relate this width to external measurements of radular stalk width, we measured the ratio of the outer to the inner widths in fixed tissue (A), in high-resolution MR images (B) and in freshly dissected tissue (not shown). (C) Radular stalk shape based on a three-dimensional reconstruction of high-resolution MR images. (D) Mid-sagittal view of radular stalk shape based on the three-dimensional reconstruction shown in C.