In a cross-sectional study 142 male and 139 female workers participated in a self-report questionnaire and a clinical examination. The aim of this study was to use the cervico-thoracic ratio (CTR), a clinical method for measuring segmental mobility between C7 and T5, to evaluate the influence of segmental mobility in neck-shoulder pain and different subjectively experienced symptoms. The study showed that reduced relative mobility at levels C7-T1 and T1-T2 significantly predicted neck-shoulder pain and the symptom weakness in the hands. The strongest relationship between segmental mobility and symptoms was found among subjects classified as having an inverse C7-T1 function, defined as equal or less mobility in motion segment C7-T1 compared to T1-T2. Reduced mobility explained 14% of neck-shoulder pain and 15% of weakness in the hands. It is suggested that deviation from synchronous distribution of mobility between motion segments C7-T1 and T1-T2 might be a factor provoking joint mechano receptors.