This study was undertaken to determine the activation and coordination
patterns of the three suprahyoid muscles-geniohyoid, mylohyoid, and a
nterior belly of the digastric muscle-in elevating the larynx during s
wallowing. Electromyographic activity was also recorded from two intri
nsic laryngeal muscles (vocalis and lateral cricoarytenoid) and the an
terior genioglossus. Ten adults served as participants. Each participa
nt produced 15 swallows of 15 mL of tap water both normally and with a
12-mm bite block placed between the molars. The electromyographic dat
a were ensemble averaged with a laboratory computer. Analyses showed t
hat the three suprahyoid muscles were used selectively by different pa
rticipants. Some participants used all three muscles for hyoid elevati
on, while others used different pairs of two of the muscles. The activ
ation patterns of the suprahyoid muscles during swallowing also varied
with respect to each other and the onset of the laryngeal constrictor
muscles; however, use of at least one suprahyoid muscle always preced
ed the onset of the laryngeal adductors, indicating that larynx elevat
ion consistently preceded glottal adduction. The way in which the musc
les responded to the bite block varied considerably both within and am
ong participants. Some maintained temporal stability but increased ove
rall muscle activity; others reorganized temporal relations either wit
h or without corresponding muscle activity adjustments. These findings
suggest that the laryngeal elevation system is an adaptive function r
ather than an immutable action.