The Effects of Forward Head Posture on Neck Extensor Muscle Thickness: An Ultrasonographic Study.

OBJECTIVE: This study aimed to compare neck extensor muscle thickness, thickness changes, and strength between participants with forward head posture (FHP) and controls with normal head posture (NHP). METHODS: Twenty college students with FHP (mean age 21.30 ± 2.36 years) and 20 students with NHP (mean age 21.85 ± 2.78 years) participated in this case-control study. The thickness of neck extensor muscles was measured at rest and at maximal voluntary isometric contraction (MVIC). In addition, the craniovertebral angle (CVA) was calculated. To compare thickness changes between the 2 groups and among 5 muscles, a 2-way repeated measures analysis of variance was applied. In addition, Pearson's correlation test was performed to investigate the relationship between neck extensor MVIC and CVA. RESULTS: The FHP group demonstrated lower MVIC compared with the NHP group (P = .03). Semispinalis capitis showed the smallest thickness changes during neck extensor MVIC in FHP compared with the controls (P < .001). However, no significant difference in terms of muscle thickness was observed between the 2 groups at the state of rest (P = .16-.99). A positive association was also found between the MVIC and CVA (P = .02). CONCLUSIONS: Semispinalis capitis had less thickness changes during MVIC of neck extensors in individuals with FHP compared with those with NHP. This indirectly implies lower activity of this muscle in FHP condition. This study finding may help researchers develop therapeutic exercise protocols to manage FHP.

Differential Activation of the Dorsal Neck Muscles During a Light Arm-Elevation Task in Patients With Chronic Nonspecific Neck Pain and Asymptomatic Controls: An Ultrasonographic Study.

BACKGROUND: Disturbance in neck muscle function is a well-known complication of chronic nonspecific neck pain (CNNP). It is, however, unclear which muscles are more susceptible to functional impairment in patients with CNNP during upper limb tasks. OBJECTIVES: To compare ultrasonographic changes in dorsal neck muscles thickness in patients with CNNP and asymptomatic controls while they performed a light load upper-limb movement. DESIGN: Case control. SETTING: University research laboratory. PARTICIPANTS: Twenty individuals with CNNP with a mean age of 23.35 ± 2.94 and 20 asymptomatic controls with a mean age of 22.30 ± 2.86, without any history of cervical diskopathy, fracture, trauma, inflammation, and spinal deformity were recruited for this study. METHODS: Ultrasonographic measurement of dorsal neck muscles thickness was performed during a light load 3-second arm-elevation task (shoulder scaption to 120°) in the 2 groups. Associations between pain intensity and patients' perceived disability and between pain intensity and muscle thickness also were evaluated at the state of rest. MAIN OUTCOME MEASUREMENTS: The thickness changes of the dorsal neck muscles throughout the arm elevation were calculated. The pain intensity and the patient's perceived disability also were measured. RESULTS: A significant main effect of muscle activity status was revealed for the multifidus and semispinalis cervicis and the splenius capitis, indicating an increase in their thickness throughout the arm elevation (P < .001). The only muscle that showed a difference between groups was the multifidus (P = .007). Direct associations between pain and disability (r = .48, P = .03) and between pain and multifidus thickness (r = -.49, P = .03) also were observed. CONCLUSION: The deteriorating effect of CNNP on the neck muscles targets the deep layer of the dorsal neck muscles (ie, the multifidus) more than the superficial muscles during light upper-limb tasks. LEVEL OF EVIDENCE: III.