What does fontanelle mean?
A fontanelle is a soft, membrane-covered gap between the bones of an infant's skull where several cranial plates have yet to fuse. Newborns have several such spaces, but the two clinically important ones are the diamond-shaped anterior fontanelle on the top of the head, which usually closes by about eighteen months of age, and the smaller triangular posterior fontanelle, which closes within the first few months. These flexible gaps allow the skull to mould during birth and to expand as the brain grows rapidly in infancy. Because changes in a fontanelle's shape can signal dehydration, raised intracranial pressure, or other conditions, physicians routinely examine them during check-ups. The word entered English from French in the seventeenth century and derives ultimately from Late Latin 'fontanella', meaning 'little fountain', a reference to the pulsing felt beneath the membrane. Though chiefly medical, the term is widely known among parents and carers.
nounA soft membranous gap between the bones of an infant's skull where the sutures have not yet fused; the term most often refers to the two principal gaps, the anterior and posterior fontanelles.
- A soft gap between the unfused cranial bones of an infant's skull, especially one of the two main ones (anterior and posterior).
"The paediatrician gently palpated the baby's anterior fontanelle during the routine check-up."
"The paediatrician noted that the infant's anterior fontanelle was flat and normal at her six-month check-up."
"A persistently sunken fontanelle can be an early sign of dehydration in newborns."
Standard plural; infants normally have six fontanelles at birth, though only two are commonly discussed.
"At birth, a full-term infant has several fontanelles, though the anterior and posterior are the ones most often examined."
The word for your baby's soft spot literally means 'little fountain' — and it's named because doctors once believed pulses beat visibly beneath it like water.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of fontanelle
Fontanelle comes from the French 'fontanelle', a diminutive of 'fontaine' ('fountain'), which traces back through Late Latin 'fontanella', meaning 'little spring or fountain'. The word entered English in the early seventeenth century, when anatomists applied it to the soft spots of the infant skull, reportedly evoking the idea of a small hollow where a pulse could be felt like the throbbing of a spring. Its deeper root is Latin 'fons' ('spring or source'), which also gives English words such as 'font' and 'fountain'.
Related word forms
How fontanelle is actually used
Almost entirely used in medical, paediatric, and childcare contexts; the register is clinical but familiar to new parents. The spelling 'fontanel' is more common in American English, 'fontanelle' in British English. The plural is typically pronounced with the final syllable unchanged (/ˌfɒn.təˈnɛlz/).
Easily confused with fontanelle
'Fontanel' is simply the standard American spelling of the same anatomical structure, while 'fontanelle' is the usual British spelling — they are not different words.