Fig. 8. Mean hyoid depression (0%–100%) and elevation (100%–200%) profiles with the calculated four-bar model output for hyoid-depression mechanism 2A (A–C, top), together with length of the sternohyoideus muscle (m-sh; A–C, bottom). Separate graphs are shown for each individual (N=20). The shaded areas accompanying each curve indicate S.E.M. Note that these S.E.M. values are larger in case the radio-opaque marker is absent at the tip of the cleithrum (B,C). The lower and upper broken, grey lines represent the output of the four-bar model with, respectively, a fully elongated sternohyoideus muscle and the sternohyoideus at minimum length. The latter curve is partly not displayed in B when there were no analytical four-bar solutions in more than half of the cases. Grey bars indicate the period during which the sternohyoideus shortens. Colour codes are indicated in the key above the figure. Mech. 2A, see Fig. 2.