What is fontanel?

Fontanel, also spelled fontanelle, soft spot in the skull of an infant, covered with tough, fibrous membrane.

Where is the fontanel on the skull?

In an infant, the space where 2 sutures join forms a membrane-covered “soft spot” called a fontanelle (fontanel). The fontanelles allow for growth of the brain and skull during an infant’s first year. There are normally several fontanelles on a newborn’s skull. They are located mainly at the top, back, and sides of the head.

What is the posterior fontanelle?

An infant’s skull consists of five main bones: two frontal bones, two parietal bones, and one occipital bone. These are joined by fibrous sutures, which allow movement that facilitates childbirth and brain growth . Posterior fontanelle is triangle-shaped. It lies at the junction between the sagittal suture and lambdoid suture.

How is an abnormal fontanel diagnosed?

A physical examination helps the physician determine which imaging modality, such as plain films, ultrasonography, computed tomographic scan, or magnetic resonance imaging, to use for diagnosis. The diagnosis of an abnormal fontanel requires an understanding of the wide variation of normal. At birth, an infant has six fontanels.