Ultrasonographic assessment of cervical and craniofacial muscle thickness in individuals with and without cervicogenic headache.

Background: Cervicogenic headache (CH) is a secondary headache disorder originating from dysfunction of the cervical spine and surrounding musculoskeletal structures. Alterations in cervical and craniofacial muscle morphology may be related to its pathophysiology. This study aimed to compare the thickness of selected head and neck muscles between individuals with and without CH using ultrasonography and to examine potential associations with clinical symptoms. Methods: A prospective cross-sectional study was conducted with 37 patients diagnosed with CH and 37 age-and sex-matched healthy controls. The thickness of the sternocleidomastoid, upper trapezius, masseter, and temporalis muscles was bilaterally measured using portable ultrasonography. Headache intensity and functional disability were assessed with standardized clinical instruments. Group comparisons and correlation analyses were performed using appropriate statistical methods. Results: Participants with CH demonstrated significantly reduced thickness in the bilateral sternocleidomastoid and right upper trapezius compared with controls. No significant differences were observed in the masseter or temporalis muscles. A moderate negative correlation was found between right trapezius thickness and disability scores, whereas headache intensity was not significantly related to muscle thickness. Conclusions: Sternocleidomastoid and upper trapezius thinning may be associated with cervicogenic headache. Ultrasonography provides a non-invasive tool for evaluating muscle morphology in this population; however, further studies are needed to clarify its clinical implications and potential role in guiding rehabilitation approaches.