Cephalic Index Demystified: What to Know About Your Baby’s Skull Shape


As a new parent, there are so many things to keep track of when it comes to your baby’s health and development. One aspect that may not be on your radar is the cephalic index, or the ratio of the width of your baby’s head to its length. Understanding this measurement can provide valuable insights into your baby’s skull shape and potential implications for their growth and development.

What is the Cephalic Index?

The cephalic index is a measurement that indicates the shape of your baby’s skull. It is calculated by dividing the width of the head by the length of the head, then multiplying by 100. This ratio is expressed as a percentage, with different ranges indicating different skull shapes.

Types of Skull Shapes

There are three main categories of skull shapes based on the cephalic index:

  • Dolichocephaly: When the cephalic index is less than 75%, it indicates a long and narrow skull shape.

  • Mesiocephaly: A cephalic index between 75% and 79% indicates a medium or average skull shape.

  • Brachycephaly: If the cephalic index is 80% or higher, it suggests a short and wide skull shape.

Why is the Cephalic Index Important?

Monitoring your baby’s cephalic index can provide valuable information about their skull development. An abnormal cephalic index can sometimes be a sign of conditions such as craniosynostosis, a rare condition where the bones of the baby’s skull fuse prematurely, affecting their head shape and potentially brain development.

Understanding Your Baby’s Skull Shape

While variations in cephalic index are normal, it’s essential to monitor any significant changes or abnormalities. Consulting with your pediatrician if you have concerns about your baby’s skull shape can help address any potential issues early on.

How is the Cephalic Index Measured?

Measuring the cephalic index typically involves using a specialized tool called a cephalometer, which is a caliper-like instrument used to determine the head’s dimensions accurately. This measurement is usually done by healthcare professionals during routine check-ups or if there are concerns about the baby’s head shape.

What Can You Do About Your Baby’s Skull Shape?

If you notice any significant changes in your baby’s head shape or have concerns about their cephalic index, it’s important to consult with your pediatrician. They can provide guidance on whether further evaluation or interventions are necessary to ensure your baby’s healthy growth and development.


Understanding your baby’s cephalic index can provide important insights into their skull shape and potential implications for their growth and development. Monitoring this measurement and consulting with your pediatrician if you have concerns can help ensure your baby’s well-being.


Q: Is it normal for my baby’s cephalic index to change over time?

A: Yes, some variations in the cephalic index are normal as your baby’s skull continues to develop. However, significant changes or abnormalities should be monitored and discussed with your pediatrician.

Q: Can I measure my baby’s cephalic index at home?

A: It’s best to leave the measurement of the cephalic index to healthcare professionals who have the necessary tools and expertise to obtain accurate results.