(1) Clinical manifestations: a: the head circumference increases rapidly after birth, the head shape becomes round, the subcutaneous veins are enlarged, the fontanelle is enlarged and elevated, the tension is high, and the fontanelle is not depressed when the child is placed in the upright position. b: the cranial sutures are separated, the head shape is rounded, and the skull bone is thinned. Enlargement of the head is seen mainly in the upper part of the cerebellar vermis, and the posterior cranial fossa is particularly enlarged in occlusion of the fourth ventricular outlet. l (Normal value of head circumference: head circumference of newborns is 33-35cm, head circumference increases about 1.2-1.3cm per month within 6 months, 8cm in total, 3cm in the second half of the year, 2cm in the second year, 2cm in the third and fourth years, and 1.5cm in total in the next 6 years, posterior fontanel closes in 6 months after birth, and fontanel closes in 9-18 months). Congenital hydrocephalus in infants and young children mostly begins to increase in size of the skull a few weeks after birth, and it is usually found gradually after 3 to 5 months, but there are also cases in which the skull is enlarged at birth, and the clinic is particularly concerned about the progressive and abnormal enlarging of the skull due to the increase of intracranial pressure, which is disproportionate to the development of the circumference of the body, and the frontal part is protruding forwards, and the top of the orbit is being pressurized downwards, and the two eyes are under-visioned, and the eyeballs are turning downwards, which causes the The upper part of the sclera is white, the fontanel is enlarged and the tension is increased, the other fontanels can also be enlarged, the skull bone sutures are separated, the veins of the scalp are dilated, and the cranial percussion shows a “pot-breaking sound”, the bone sutures of the infants and young children are not closed, and the cranium can be compensated for the enlargement when the intracranial pressure is increased, so the symptoms of the increased intracranial pressure in early stage may be inconspicuous, but when hydrocephalus is serious and progresses rapidly, the symptoms may also appear. However, when hydrocephalus is severe and progresses rapidly, it can also appear, and its symptoms include repeated vomiting, degenerative brain changes, brain development disorders, central paralysis of the limbs, especially the lower limbs, intellectual changes and developmental disorders, optic nerve compression and atrophy, which can lead to blindness, nystagmus, convulsions, and is often accompanied by malformations in other parts of the body.