Neck pain is one of the leading causes of disability globally, being a condition with high recurrence and chronicity. In patients with chronic pain, psychological, anatomical, professional, sociocultural, and biological profiles are determinants of the severity and duration of pain episodes. Although physical therapy provides tools to assess these factors, the analysis of the histology, size, and shape of the musculature in the cervical region is one of the main limitations in cervical pain research. While the gold standards are computed tomography and magnetic resonance imaging, these imaging methods are expensive, require prolonged examination time, and cannot be routinely used in clinical practice. Ultrasound is a feasible, fast diagnostic tool, offering real-time imaging at a lower cost (in both materials and human resources). The objectives of this project are: 1) to conduct a validation study of panoramic ultrasound for analyzing the size, shape, and histology of structures located in the cervical region, comparing the ultrasound characteristics with the values obtained from magnetic resonance imaging; 2) to assess the reliability of measurement procedures in both experienced and inexperienced operators in healthy participants and those with cervical pain; 3) to compare reliability across different segments; 4) to analyze the correlation between ultrasound metrics, clinical severity indicators, sociodemographic characteristics, and psychosocial factors; and 5) to analyze sex and side differences in clinical and asymptomatic populations, as well as differences between cases and controls.