Question
A 7-year-old child has a head circumference of 48 centimeters. Does this mean they have microcephaly? The child’s developmental status includes: able to walk, speaking simple words by the age of three (such as ‘Dad’, ‘Mom’), hyperactive and fond of throwing things before the age of three, able to understand adults’ words and follow instructions. At the age of four, they attend kindergarten, can read but cannot write, can recite texts and ancient poems, but have a blurred concept of numbers and cannot count objects. Under adult prompts, they can count up to one hundred, have difficulty concentrating, and often have a distracted gaze when answering questions. It seems that the child was previously quite intelligent, but their intellectual development seemed to stagnate between the ages of four and five, with insufficient language expression ability and unable to express their own thoughts.Brain MRI and CT scans show normal results, while EEG shows abnormalities. The child is currently undergoing rehabilitation training at Kangtong.
Answer
Head circumference refers to the circumference measured from the highest point of the temporal bone above the eyebrows, around the occipital bone nodes, and back to the starting point. It is closely related to the growth and development of the brain and skull. The average head circumference at birth is about 34 centimeters, with an increase of approximately 8-10 centimeters in the first six months, and 2-4 centimeters during the subsequent year’s growth period. At six months old, it is 44 centimeters, at one year old it is 46 centimeters (the same as chest circumference), at two years old it is 48 centimeters, at five years old it is 50 centimeters, and at fifteen years old it reaches an adult range of 54-58 centimeters. The size of the head circumference reflects the growth of the brain and skull.