Rickets is a chronic nutritional disease caused by vitamin D deficiency that leads to disturbed calcium and phosphorus metabolism in the body, causing abnormal skeletal development. If a square skull is observed, it indicates that the child's disease has entered an active phase. Generally, in the early stages, there is an enlargement of the fontanelle or a delay in the closure of the fontanelle. By seven to eight months, a square skull can appear, primarily characterized by outward bulging centered on the frontal and parietal bones. At this time, it is generally necessary to administer a sufficient dose of vitamin D and encourage appropriate outdoor activities. Depending on the child's condition, it might be appropriate to supplement with calcium as well. Gradually, this should be curable; however, if there are other special causes for the abnormal vitamin D levels, such as severe liver or kidney disease or some new genetic diseases causing square skull, the treatment might be more challenging.