Fig. 8. Quantitative results of the radula-centric kinematic model of swallowing. (A) Shape space analysis of one of the magnetic resonance imaging (MRI) swallowing sequences used to construct the radula-centric model (sequence 5385-S1, frames 116-133). Note that the entire plot is shifted to the right along the ellipticity axis (i.e. less elongated along the antero-posterior axis) compared with Fig. 3C (mean transilluminated juvenile shape space plot) as a result of the presence of elastic tissue around the jaws that is opaque to transillumination but is distinctly different from the I1/I3 muscles (see Fig. 5D). (B) Shape space analysis of the radula-centric kinematic model, which is a composite of several MRI swallowing sequences. There is only rough agreement with A, probably because B is a composite of 4-9 different swallowing sequences. There is a large hysteresis loop in frames 29-37. The gray symbols marking key events of the feeding cycle in A and B are defined in Fig. 3C. (C) Model I2 and I7 muscle lengths. I2 nearly triples and I7 quadruples its length during t1. Intervals t1,t2,t3 and t4 are defined in Materials and methods. (D) Model I1/I3 muscle antero-posterior length. (E) Model I1/I3 muscle ring widths (medio-lateral). Ring 1 (posteriormost) is at the lateral groove, and ring 5 (anteriormost) is at the opening of the jaws. Note the rapid changes in the widths at mid-t4 (rings 3-4), mid-t1 (rings 1-5) and t3 (rings 1-2). MRI frames are 250 ms (real time). Model frames represent 66.7 ms (normalized).