Microcephaly can be divided into true microcephaly and relative microcephaly. True microcephaly is mostly caused by an autosomal abnormality, or fetal radiation or intrauterine infection, especially in early gestation, showing that the brain gyrus is too small, or no brain gyrus, brain development is significantly delayed, often in the third to fifth month of fetal life, the patient’s head is small and pointed, flat forehead, head circumference is smaller than the chest, the largest does not exceed 43 cm, the smallest can be below 25 cm, brain weight of 900 grams The head circumference is smaller than that of true microcephaly. The degree of head circumference reduction is less than that of true microcephaly. The main manifestation of this disease is that after the completion of brain development, the weight of the brain is obviously lighter than normal, and the brain gyrus is too small or there is no brain gyrus at all. The development of the brain is significantly delayed, and even in the third to fifth month of infancy, the development stops. As a result, the child’s head becomes small and pointed, with a sunken nasal bridge, large ears, a receding lower forehead, and a narrow forehead with an extraordinarily small head circumference, up to less than 42 cm. The child’s forehead and occipital area are flat, and the fontanelle and bone gap close early. Physical development is obviously abnormal, and mental development is significantly delayed. Some children even have twitching, stiffness of limbs or tardive dyskinesia and paralysis. 2.Examination and treatment Treatment Treatment of this disease should be carried out after cranial photographs and three-dimensional CT, cranial MRI and other examinations, and for those with elevated intracranial pressure, surgery should be performed as early as possible. For children with simple premature closure of bone suture, neurosurgical treatment can be used, which can achieve certain efficacy. The aim of surgical treatment is to enlarge the cranial cavity, relieve the intracranial hypertension, enable the development and growth of the compressed brain tissue and cranial nerves, and perform cranioplasty in parallel. For children with cerebral dysplasia, surgical treatment is not effective. Surgical treatment is performed to remove the prematurely closed bone suture and then perform cranioplasty to achieve decompression and facilitate brain development as well as improvement of appearance. The timing of surgery depends on the condition, usually at the age of 6-7 months, once neurological atrophy and intellectual impairment occur, even if surgery is performed, the function is not easily recovered.