Fig. 8. Kinematics of the antero-posterior length of the I3 muscle during swallowing. (A-D) Data plotted as length (mm) as a function of time (ms). Left panels show the antero-posterior length of the I3 muscle on the dorsal surface. Right panels show the antero-posterior length of the I3 muscle on the ventral surface. (A) I3 kinematics in the first swallow. (B) I3 kinematics in the second swallow. (C) I3 kinematics in the third swallow. (D) I3 kinematics in the fourth swallow. (E) Normalized, averaged and smoothed anterio-posterior lengths of I3 during the swallowing cycle. Data are shown as mean ± 1 S.D. (F) Schematic diagrams indicating the antero-posterior length of I3 on the dorsal surface for frames 1, 9, 17, 18 and 22, highlighted with a black line. The antero-posterior lengths of I3 on the ventral surface for frames 1, 9, 18 and 22 are shown on the right, highlighted with a black line. Compare original frames in Fig. 5. For definitions of periods t1, t2 and t4, see Materials and methods.