Many neurological disorders in infants are reflected in the child’s head circumference and fontanelle. This article introduces how to properly measure the head circumference and fontanelle. I. Head circumference measurement Measuring tools: one soft ruler with scale Measuring steps: 1. find the baby’s eyebrow arch, which is the highest point of the eyebrow 2. place the zero point of the soft ruler (0cm) on the midpoint of the line connecting the eyebrow arch, take this as the starting point, and prepare to measure 3. wrap the soft ruler along the level of the eyebrow arch behind the baby’s ear, find the upper edge of the left or right ear, then find the occipital ridge (the location of the most convex point at the back of the head), wrap it around this point, and put the soft ruler back around the front. The soft ruler should be overlapped and crossed, and the number at the cross is the baby’s head circumference. Warm tips: 1. The gaps converge at one point, forming the fontanel. In addition to fontanel, there is also bregma. The fontanelle is mainly formed by the confluence of the gap between the frontal bone and the parietal bone, and is rhombic in shape, generally about 2cm in size at birth, and the size changes gradually with the growth of the skull later, and the closing time is generally 1-1.5 years old, mostly within 2 years old, but there are individual differences in the specific time. The posterior fontanelle is the gap between the parietal and occipital bones, which is usually very small at birth or already closed, and closes at the latest 2-4 months after birth. Small, large, or abnormally shaped fontanelles indicate problems such as microcephaly, premature closure of the cranial suture, postural head tilt, vitamin D deficiency, hydrocephalus, and cranial hypertension. The fontanelle is generally slightly sunken or flat and soft to the touch compared to the rest of the body, and is normally rhombic in shape, with a slight pulsation that can be seen with breathing upon closer inspection. Notes on recording fontanel: 1. Be sure to measure in a calm state 2. Accurately record the front and back length and left and right length of fontanel 3. The size of fontanel is the result of dividing the sum of the front and back length and left and right length by 2. 4. The tension of fontanel is soft = lips, medium = tip of nose, hard = forehead