If a small infant has an inward thumb in the palm and cannot straighten it, it is called the cortical thumb sign, which is abnormal. This can be corrected by the following methods: 1. Massage the thumb, parents hold the child’s wrist with one hand, and with the other hand, massage the inward thumb, in the direction of extension. Each time the massage is done, fix the baby’s thumb and keep it extended for 30 seconds, repeatedly massage for 2-3 minutes, several times a day. 2, during the day when the baby is awake, use a toy as thick as a small banana, placed in the palm of the hand, so that the baby pinches and holds the toy with the thumb and other fingers to stop the thumb inward. 3, at night when sleeping, wrap a handkerchief around the root of the thumb to help separate the thumb from the palm of the hand, in the wrist Tie a knot on the other side of the wrist to prevent the thumb from closing in.