Objective: Neck pain is one of the most common musculoskeletal disorders. Structural and functional alteration of cervical muscles is a commonly-reported complication of chronic neck pain (CNP). Measurement of muscle thickness is an acceptable way to evaluate muscle morphological structure. Therefore, this study aimed to measure cervical extensor muscles thickness in individuals with chronic nonspecific neck pain and healthy controls using ultrasonography so as to evaluate structural differences between the 2 groups.

Materials & Methods:  A total of 30 female volunteers (15 individuals with nonspecific CNP and 15 controls) participated in this casual comparative  study. Thickness of cervical extensor muscles, including multifidus, semispinalis cervicis, semispinalis capitis, splenius capitis, and upper trapezius at the level of the forth cervical vertebrae were measured using ultrasonography in resting position. Independent t test was performed to analyze the data by using the spss 20 software.

Results: The thicknesses of cervical multifidus and semispinalis cervicis muscles in patients with CNP were smaller than those of controls with P=0.03 and P=0.01, respectively. There were no significant differences between two groups regarding the thicknesses of semispinalis capitis, splenius capitis, and upper trapezius muscles (P>0.05).

Conclusion: Reduced multifidus and semispinalis cervicis thickness seen in the present study indicates deep neck extensor muscles atrophy and weakness in patients with neck pain. However, there were no differences between two groups with regard to superficial muscles thicknesses. Accordingly, exercise therapy for deep muscles should be considered in the management of patients with nonspecific CNP.