Background:The purpose of this study was to observe the difference and explore the correlation of the deep cervical muscles’ size by high-frequency ultrasound and the posture index
between the patients with chronic neck pain (CNP) and the healthy subjects, for providing the more effective exercise therapy approach for patients with chronic neck pain.
Methods:Thirty nine patients with CNP were recruited according to the inclusion criteria as the study group and twenty one healthy subjects as the control group. The anterior
posterior dimension (APD) and lateral dimension (LD) of the semispinalis capitis (SEC) and the deep cervical flexors(DCF) were measured by high-frequency ultrasound. The forward head angle (FHA) and
forward shoulder angle(FSA) were measured as the posture index. All of the measured data were collected and analyzed. The correlations between FHA or FSA and muscles sizes were determined using
Pearson’s correlation coefficient.
Results:The dimensions of the SEC did not differ between two groups (P >0.05). There was a significant difference in the LD of the DCF between two groups (P<0.05). There was no
difference in the APD of the DCF between two groups (P>0.05). There were both most significant difference in the FHA and FSA between two groups (P<0.01).There was a positive correlation between FHA
and FSA (r=0.444，P<0.01). There was a negative correlation between FSA and the thickness of DCF (r =-0.391, P<0.05).
Conclusions:Patients with chronic neck pain had smaller dimensions of the deep cervical flexors compared to healthy subjects. They had greater forward head angle and forward shoulder
angle, and the greater the forward head posture, the greater the forward shoulder posture. Patients with smaller dimensions of the deep cervical flexors had greater forward shoulder posture. The
training of the deep cervical flexors should be enhanced in exercise therapy for patients with chronic neck pain.