If the fontanel is still not closed at 2 years and 3 months old, it is usually considered to be related to hydrocephalus and rickets and other diseases. Different causes are associated with different treatment measures, so it is important to consult a doctor to find out the cause of the problem and then provide targeted treatment. Normally, fontanel is divided into anterior fontanel and posterior fontanel, of which the posterior fontanel closes earlier, usually around 3 months of age. The anterior fontanel closes later, usually around 1-1.5 years after birth. If the fontanel has not closed by 2 years and 3 months, it is usually related to pathologic factors. 1. Hydrocephalus: Hydrocephalus can lead to increased intracranial pressure, which enlarges the fontanel, causing it to close later than in children of the same age. The treatment of hydrocephalus is mainly to reduce the production of cerebrospinal fluid. Commonly used drugs include the diuretic furosemide and the diuretic dehydrator mannitol. For severe cases, relief through lateral ventricular external drainage can also be considered. 2. Rickets: Rickets is a multifactorial class of abnormal calcium and phosphorus metabolism, which can cause softening of the child’s skull, enlarged fontanel and delayed closure. The treatment is based on vitamin D and calcium supplementation, usually need to pay attention to strengthen nutrition, ensure enough milk. In addition, you should take your child to participate in outdoor activities and get more sunshine. If the fontanel is still not closed at 2 years and 3 months, there may be other causes, so parents are advised to take their children to the hospital to clarify the cause of the disease and then carry out targeted treatment.