How should head circumference be measured for infants?

Measuring an infant's head circumference accurately is critical for assessing their growth and development. The proper method is to use a flexible measuring tape that conforms closely to the shape of the head. The circumference should be taken at the largest part of the forehead and around the occipital bone at the back, ensuring the tape is snug but not too tight.

Measuring to the nearest 0.6 cm allows for a precise evaluation that is useful for tracking subtle changes in head size over time. This level of precision is particularly important in pediatric care, as even small changes can signal a potential health concern. By capturing measurements at such a minute interval, healthcare practitioners can make informed decisions about an infant's growth compared to established growth standards.

Other methods of measurement provided in the options do not offer that same level of specificity that is typically required in clinical practice for monitoring developmental progress in young children.