In the outpatient clinic, we have seen many children and adolescents whose families brought them for checkups, and all the tests showed no problems. The majority of girls are inwardly oriented, while outwardly oriented is rare. According to years of clinical observation, the following points are summarized for your reference. In general, in the absence of obvious causative factors, the internal and external hips are caused by the hip joint. A small number of children with cerebral palsy have internal rotation caused by high tone in the lower extremity muscles, except for internal rotation. It is the forward approach of the greater trochanter to the anterior part of the pelvis. External rotation is the opposite movement of the greater trochanter. If it is greater than 125 degrees, it is called internal rotation of the hip; if it is less than 125 degrees, it is called external rotation of the hip. As shown in the figure, the normal femoral neck stem angle: Third, as shown in the figure below, the femoral head is at an angle with the left and right penetration surface of the human body, called the anterior tilt angle, this angle is the internal and external rotation angle of the hip joint. In general, the anterior tilt angle <12 degrees, there is a tendency to external rotation when walking; anterior tilt angle >12 degrees, the femoral head is partially exposed when walking, walking in order to keep the femoral head in the acetabular fossa, there is a tendency to internal rotation when walking. In children, increased or decreased anteversion is more common and usually disappears with growth and development. However, families should be cautious with this phenomenon. If there is a tendency to aggravate it within a short period of time, it is advisable to consult a professional rehabilitation institution for medical consultation.