Key takeaways: Babies have two main soft spots (fontanelles). The back one usually closes by about 2 months, and the front one usually between about 12 and 18 months, with a wide normal range. Gentle touching and washing are safe. A bulging soft spot when your baby is calm and upright, or a sunken one, needs a call.
A newborn’s skull is made of several bony plates with flexible seams (sutures) between them. Where the seams meet are soft, flexible areas called fontanelles. They allow the head to change shape during birth and give the brain room to grow.
The Two Main Soft Spots
- Anterior fontanelle: the larger, diamond-shaped soft spot on the top of the head. It usually closes between about 12 and 18 months, though the normal range is wider.
- Posterior fontanelle: a smaller, triangle-shaped spot at the back of the head. It usually closes by about 1 to 2 months.
What’s Normal
- The soft spot may look slightly flat or slightly dipped when your baby is calm and upright.
- It may bulge a little when your baby cries, strains, or lies down.
- You may see it pulse with your baby’s heartbeat.
- It’s safe to touch gently, wash, and brush over. A tough membrane protects the brain.
Bulging Soft Spot
A soft spot that stays tense or bulging when your baby is calm and upright can be a sign of increased pressure inside the skull, which may be caused by infection such as meningitis, bleeding, or fluid buildup. It needs prompt evaluation, especially with fever, vomiting, irritability, or sleepiness.
Sunken Soft Spot
A noticeably sunken soft spot can be a sign of dehydration, especially with fewer wet diapers, a dry mouth, or lethargy.
Closing Too Early or Too Late
- Early closure can sometimes be a sign of craniosynostosis, where skull seams fuse too early and affect head shape. Your doctor checks head shape and size at each visit.
- Late closure can be associated with some medical conditions, but many babies with larger soft spots are healthy. Your doctor will look at overall growth and development.
Call your baby’s doctor promptly if: the soft spot bulges when your baby is calm and upright, especially with fever, vomiting, unusual sleepiness, or irritability; or if it looks sunken with signs of dehydration. Call 911 for seizures or if your baby is hard to wake.
The Bottom Line
Soft spots are normal, protected, and safe to touch. Watch for a persistent bulge or a sunken look, and let your doctor track closure and head growth at well visits.
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Sources
- Kiesler J, Richer R. The abnormal fontanel. Am Fam Physician. 2003;67(12):2547-2552.
- Altmann TR, Hill DL, eds. Caring for Your Baby and Young Child: Birth to Age 5. 7th ed. American Academy of Pediatrics; 2019.
- Lewis ML. A comprehensive newborn exam: part I. General, head and neck, cardiopulmonary. Am Fam Physician. 2014;90(5):289-296.
This article is for general education and is not a substitute for individualized medical advice. Always talk with your baby’s health care provider or your own provider about your specific situation. If you think your baby or you may have a medical emergency, call 911.
