Pediatric strabismus may be the result of contracture of the sternocleidomastoid muscle on one side or a congenital neck malformation, and the etiology of congenital strabismus is not well understood at this time. Many people believe that it may be related to abnormal pressure in the uterus, or malposition of the fetus, and it is also believed that obstructed labor is one of the causes of strabismus, but no conclusive evidence has been obtained. Usually after birth, children with strabismus can be found with their head tilted to the affected side and their face rotated to the tendon side, and the symptoms become more pronounced 2-3 weeks after the fetus is born. The affected child’s ability to turn his/her head to the healthy side is clearly limited, but a mildly strabismic child can only be detected on close inspection, and on examination, a lump in the child’s neck will be found. If the child is suspected of having congenital strabismus, a localized ultrasound can be used to make a definitive diagnosis.