This study will collect the children younger than one year-old who were impressed or suspected to have torticollis in physical medicine and rehabilitation clinic to assess the relationship between digitalization results of ultrasound image and clinical manifestations and prognosis. Digital image analysis of ultrasound which contains both sides of the SCM in transverse and longitudinal view for comparison of lesion side and sound side will be performed after the initial enrollment and every six months later. Evaluation of clinical manifestations includes measurement of side difference of angles in bilateral neck lateral flexion, rotation and habitual head position will performed using an arthrodial protractor by a trained member at the beginning of physical therapy and one month later, then every 2-3 months. All cases will be followed for 1 and a half years. We expect to find some typical characteristics of CMT through digital analysis of the SCM. These characteristics include the muscle thickness and intensity of echogenicity in the region of interest. The Pearson's correlation will be performed to analyze the relevance of quantitative side differences in ultrasonography and clinical manifestations including side differences of neck rotation, lateral flexion and habitual head position between lesion sides and sound sides.