What is the average diameter of the posterior fontanelle?

The average diameter of the posterior fontanelle is typically in the range of 0.5 to 1.5 cm. This small, diamond-shaped soft spot on a newborn's skull, located at the junction of the sagittal and lambdoid sutures, is often a point of assessment in pediatric examinations. It generally closes by 2 to 3 months after birth, and its size can provide important information regarding the infant's growth and development. Understanding the dimensions of the posterior fontanelle is crucial for healthcare providers, as it has implications for cranial development and can help identify potential health issues if abnormalities are present.