Nine-year-old girl breast nucleus development can see child health department, endocrinology, neurology and other departments. 1. Children’s Health Department: There are many causes of precocious puberty in children. Most children with precocious puberty usually have a bone age that exceeds their actual age, which is determined by X-rays of the hands and wrists. There is also the possibility of exposure to estrogen-containing drugs and food, etc., which can be examined in the Department of Child Health. 2. Endocrinology: Endocrinology is an important department for precocious puberty. Precocious puberty in children may be due to premature activation of the hypothalamo-pituitary gonadal axis, which can be tested for GnRH (gonadotropin-releasing hormone) stimulation. Central precocious puberty may also occur in untreated primary hypothyroidism, and T3 and T4 (thyroid hormone) tests may be performed. 3. Neurology: Certain central system abnormalities and intracranial tumors can cause precocious puberty, such as hypothalamic malformation astrocytoma. Cranial CT and MRI can be performed.