This study will collect the children younger than 1 y/o who were impressed or suspected to have torticollis in physical medicine and rehabilitation clinic. The case number is estimated around 60 in a 3-year-period enrollment. . Exclusion criteria include torticollis by other known causes like strabismus, trauma, neurogenic problems, congenital malformation or bony deformity (e.g. hemivertebrae of cervical spine). Informed consent will be given to the parents before enrollment.