Ultrasonographic analysis of sucking behavior of newborn infants: the driving force of sucking pressure.

The sucking behaviors of 15 low-risk full-term newborns were observed with ultrasonography and a special device directly measuring sucking pressure. In this study, the sequential changes in the movement of a tongue and other intra-oral structures and the sequential changes of the sucking pressure were successfully examined simultaneously. It was indicated that sucking pressure could be generated by sequential changes of an intra-oral volume caused by a peristalsis of the tongue in the sucking behavior.