Craniofacial Muscles

246 Z.-J. Liu
Fig. 14.4 Deformational pattern of tongue base and accompanying muscle activities during
voluntary bolus ( a ) and spontaneous salivary ( b ) swallowing. BWA and BWP base anterior (#1–#2)
and posterior (#3–#4) widths; BL base length (#1–#3); BT base thickness (#1–#5); MA masseter;
GG genioglossus; SG styloglossus; TH thyrohyoid; MC middle pharyngeal constrictor; Ppres palatal
pressure; Flow, Pres. and Vol respiratory air fl ow, pressure, and volume. Refer to Fig. 14.1b for
the locations of crystal pairs. Red arrows indicate swallowing episode
posterior width and shortening in length of the tongue body, along with the activity
bursts in styloglossus. The time analysis clearly indicated that the reversals of
expansion–contraction of various dimensions of the tongue body are not synchronous
but occur in a sequential manner as a function of performing tasks. Therefore,
we may conclude that: (1) tongue internal deformations are task-speci fi c in both
timing and amplitude; (2) these deformations are dominant in the transverse plane
(width and thickness) for chewing, sagittal plane (length) for ingestion, and symmetric
in both planes for drinking (Fig. 14.3 ) (Shcherbatyy and Liu 2007 ) .
Our group has also examined the internal deformations of the tongue base
(Fig. 14.1b ) in relation to respiration in the same pig model. During the inspiration