Relationship between facial morphology on lateral skull radiographs and sEMG activity of neck and trunk muscles in Caucasian adult females. A cross-sectional study.

OBJECTIVE

To evaluate whether there is an association between facial morphology on cephalometrics and surface electromyographic (sEMG) recordings of head, neck and trunk muscles.

MATERIALS AND METHODS

31 Caucasian adult females, average age 26 years (range 21-29) underwent lateral skull radiographs in natural head position (mirror position) and the sEMG recordings for the following muscles: masseter, anterior temporal, digastric, posterior cervicals, sternocleidomastoid, and upper and lower trapezius. All muscles were monitored in the mandibular rest position, and during maximal voluntary clenching (MVC).

RESULTS

Spearman's correlation coefficient revealed significant correlations (P<0.01): (i) between the variables controlling mandibular position, and the inclination of the lower incisors, and the sEMG activity of the trapezius; (ii) between the sEMG activity of sternocleidomastoid and the variables indicating the height of the mandibular ramus; (iii) between the sEMG activity of anterior temporal and the incisive angle, the inclination of the upper incisors and the maxillary base length, and (iv) between the sEMG activity of cervical muscles and the anterior cranial base length.

CONCLUSIONS

Some associations between cephalometric variables and sEMG of the neck and trunk muscles were observed. However, in view of the cross-sectional nature of the study and the limited sample, no conclusion was possible about the mechanism concerning these results. Future longitudinal studies are required to investigate the "mechanism at work".