Four-dimensional, also known as four-dimensional ultrasound, four-dimensional ultrasound may be able to detect the child’s foot inversion, but it is not absolute, and not all children with the disease can be detected. Generally in the 22-28 weeks of pregnancy go to the hospital to do four-dimensional ultrasound examination, the examination of the fetal limbs are movement, a section is difficult to complete the examination, need to sweep more than one aspect of the foot morphology ultrasound sweep can identify the foot plate and calf of the relationship between the calf and the foot when the calf and the foot of the normal posture change in the calf longitudinal section of the calf at the same time shows the calf and the foot should be considered to be the foot of the inversion. Not all inversion of the foot can be detected by 4D ultrasound, inversion of the foot is relatively mild, it is more difficult to detect by 4D ultrasound, even if you check the inversion of the foot, you can wait until the baby is born to correct it. The phenomenon of neonatal inversion of the soles of the feet may be the fetus in the uterus two feet pressure, muscle strength development imbalance caused by the phenomenon is not a deformity, the examination of the foot of the medial soft tissues of the flaccid, in the postnatal weeks will gradually return to normal. Some newborns with inward turning of the foot are congenital malformations and should consult a doctor for corrective treatment in time. It is important to do a good maternity checkup during pregnancy so that any problems can be detected and dealt with in a timely manner.