An Electromyographic Study of the Musculus Uvulae

Abstract

The musculus uvulae and the Ievator veli palatini muscle were studied with electromyography (EMG) in three normal young adult subjects. Patterns of EMG activity for the musculus uvulae were similar to those of the Ievator veli palatini for all three subjects. When differences in EMG activity between the two muscles were found, the tasks did not involve speech. The presence of the musculus uvulae along the nasal aspect of the velum may be important in filling the space between the elevated velum and the posterior pharyngeal wall. In addition, the mus-culus uvulae may function to modify stiffness of the tissue adjacent to the insertion of the Ievator veli palatini and to produce extension of the velum. From anatomic evidence it is generally acknowledged that the levator veli palatini muscle is of a size and alignment to play a primary role in velopharyngeal closing movements (Kuehn, 1979). This View has been supported by elec-tromyographic (EMG) data showing this muscle is active consistently in relation to velar closing movements (Fritzell, 1969; Bell-Berti, 1976). However, other muscles of the velopha-ryngeal complex, specifically the palatoglos-sus, the palatopharyngeus, and the superior pharyngeal constrictor, also show activity re— lated to velopharyngeal movements and may be involved in positioning the velum during speech (Seaver and Kuehn, 1980; Kuehn et a1, 1982). In contrast, the tensor veli palatini does not have an anatomic alignment that is advantageous in velar movements and its lack of involvement in speech is supported by EMG evidence (Fritzell, 1969).