An electromyographic analysis of the deep cervical flexor muscles in performance of craniocervical flexion.
OBJECTIVE
This study evaluated an electromyographic technique for the measurement of muscle activity of the deep cervical flexor (DCF) muscles. Electromyographic signals were detected from the DCF, sternocleidomastoid (SCM), and anterior scalene (AS) muscles during performance of the craniocervical flexion (CCF) test, which involves performing 5 stages of increasing craniocervical flexion range of motion--the anatomical action of the DCF muscles.


METHODS
Ten volunteers without known pathology or impairment participated in this study.


METHODS
Root-mean-square (RMS) values were calculated for the DCF, SCM, and AS muscles during performance of the CCF test. Myoelectric signals were recorded from the DCF muscles using bipolar electrodes placed over the posterior oropharyngeal wall. Reliability estimates of normalized RMS values were obtained by evaluating intraclass correlation coefficients and the normalized standard error of the mean (SEM).


RESULTS
A linear relationship was evident between the amplitude of DCF muscle activity and the incremental stages of the CCF test (F=239.04, df=36, P<.0001). Normalized SEMs in the range 6.7% to 10.3% were obtained for the normalized RMS values for the DCF muscles, providing evidence of reliability for these variables.


CONCLUSIONS
This approach for obtaining a direct measure of the DCF muscles, which differs from those previously used, may be useful for the examination of these muscles in future electromyographic applications.
D000328:Adult; D000704:Analysis of Variance; D002574:Cervical Vertebrae / Q000502:physiology*; D004576:Electromyography; D005260:Female; D019416:Head Movements / Q000502:physiology*; D006801:Humans; D008297:Male; D020393:Manipulation, Spinal / Q000379:methods*; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology*; D018583:Pliability; D016059:Range of Motion, Articular / Q000502:physiology*; D015203:Reproducibility of Results; D012399:Rotation; D016683:Supine Position