Fontanelles: What Are the Soft Spots on Baby’s Head?
If you’re cradling your little one and feel a soft spot on baby’s head, don’t freak out—this is completely normal. These soft spots, also called fontanelles, are crucial during birth and for baby’s growth and development. But why? When do soft spots close? And—um—is it normal for these soft spots to pulsate?
If you’re fuzzy on the ins and outs of fontanelles, you’re not alone. And if you’re pregnant or a new parent, it’s important to know about them so you can properly care for your newborn—and troubleshoot any issues. Read on for what you need to know about fontanelles.
- Fontanelles are the soft spots on baby’s head where the bones in their skull haven’t yet fused together. There are six fontanelles total, but the main ones are the anterior and posterior fontanelles.
- These soft spots allow baby to squeeze through the birth canal, as well as allow for the brain to grow as quickly as it does during that first year of life.
- Babies’ fontanelles will start to close around 2 to 3 months and should be fully closed around the 18-month mark.
- Baby’s soft spots don’t require too much extra care—just be gentle with them and don’t push on them. If a fontanelle is sunken, it could be a sign of dehydration.
- Reach out to your pediatrician if baby’s fontanelles are bulging or if they’ve been hit and baby’s behavior has since changed.
Fontanelles (also spelled fontanels) are just a fancy name for the membrane-covered soft spots on baby’s head where the bones have yet to fuse together. “They’re basically defects in the bone that allow the skull and brain to grow very quickly in that first year,” says Danelle Fisher, MD, the chair of pediatrics at Providence Saint John’s Health Center in Santa Monica, California. You may even feel the overlapped bones as “ridges” in baby’s skull, according to the American Academy of Pediatrics (AAP).
Naline Lai, MD, FAAP, a pediatrician at Children’s Hospital of Philadelphia, compares a newborn baby’s skull to the continents in the world: “It starts out as separate pieces and they gradually form into a skull.” Babies actually typically have six fontanelles at birth. The most notable of the soft spots are called the anterior fontanelle and the posterior fontanelle.
Where is the anterior fontanelle on baby’s head?
The anterior fontanelle is the soft spot near the front of baby’s head. “If you draw a line between your ears where a headband would sit, that’s where the anterior fontanelle is,” Lai says. “It sits in the middle there.” The anterior fontanelle is the largest, and Fisher says it’s “pretty visible on some babies.”
Where is the posterior fontanelle on baby’s head?
The posterior fontanelle is toward the back of baby’s head. “It’s where a high ponytail would be,” Lai explains. “It’s usually very tiny.”
Where are the mastoid fontanelles on baby’s head?
Baby has two mastoid fontanelles on their head at birth (one on each side). The mastoid fontanelles are located where the temporal, parietal and occipital bones meet, explains Rebekah Mustaleski, CPM-TN, a certified professional midwife and compression director with Motif Medical. These soft spots are right behind the ear, where you might tie pigtails on either side; they’re much less pronounced and noticeable than the anterior and even posterior fontanelles.
Where are the sphenoid fontanelles on baby’s head?
Baby also has two sphenoid fontanelles on either side, located where the sphenoid, temporal, parietal and frontal bones of the skull meet. This is the spot on your skull right behind the temples on either side of the head. These fontanelles are also a lot less noticeable.
One major reason babies have soft spots on their head is to help them squeeze through the birth canal during birth. “If baby is going through the birth canal, the head and shoulders are very big,” Fisher says. Having soft spots allows the head to get “squished together to get through the birth canal,” she adds. The soft spots also allow for “rapid growth of the brain,” which is developing quickly, reiterates Fisher.
Those anxiety-provoking soft spots on baby’s noggin are almost closed! Well, the back one I think is already closed! The front one is maybe an inch in diameter, if that. Remember when they were so new and so little and those soft spots seems so big and squishy! Crazy how the human body works.
While every baby is different, you can generally expect the posterior fontanelle to close around 2 to 3 months, and the anterior fontanelle to close by 18 months, Lai says. According to experts, the sphenoid fontanelles will close around 6 months old, while the mastoid fontanelles will close between 6 and 18 months old.
Your baby’s fontanelles are something your pediatrician will track at their check-ups, but if you notice baby’s soft spots are closing sooner or later than these time frames, flag it with them. “[This could] indicate certain medical conditions,” Mustaleski explains, such as craniosynostosis, Down syndrome and achondroplasia.
Because of the fontanelles, newborns are sometimes born with a “cone head” after a vaginal delivery since they just squeezed through the birth canal, Fisher says. “It should get filled in with bony cells and closed. The head shape should eventually be nice and round.”
The fontanelles provide gaps for the bones to move during the first few months of life, so any pressure on the skull can influence baby’s head shape. “Because these parts of the skull move around a little bit, they’re not sealed,” Lai says. “If you press on any area, you can flatten that part of the skull.”
This includes back sleeping. While you should follow the AAP guidelines to place baby on their back for sleep, this can cause a flat spot to form in the back of the head, Lai points out. “If you lie down on your back to sleep, and you spend the rest of the day looking up at your parents, you’ll get a flat back of the head,” she says. To avoid plagiocephaly (aka flat head syndrome), many pediatricians encourage giving baby tummy time during the day.
I was feeding baby and reached down to kiss her little head and kissed right on her soft spot. It kind of freaked me out—I never realized how soft it was!
While you’ll want to be gentle with baby’s fontanelles, they don’t require too much care or need to be tended to. Per the AAP, even though fontanelles don’t have bone protection just yet, they can withstand typical day-to-day handling. “The soft spots on baby’s head are a normal part of newborn life and are important for brain growth and development,” Mustaleski says, adding, “Be gentle with a baby’s soft spots and avoid putting direct pressure on them.” As Lijlkm, a community member on The Bump notes, “If the soft spot were as fragile as it seems, we wouldn’t have lasted very long as a species.”
Sunken fontanelles
A sunken soft spot can be a sign of dehydration, Lai says. However, the AAP says not to worry too much about this, as sunken soft spots can be present even when baby isn’t dehydrated. Instead, to gauge whether or not baby’s getting enough fluids, look for other signs of dehydration, such as fewer wet and dirty diapers and fewer tears.
For the most part, baby’s fontanelles aren’t something you need to worry about. But there are a few situations when it’s a good idea to talk to your pediatrician about baby’s soft spot.
- Baby has a bulging fontanelle. If a soft spot is “popping up,” it can be a sign of pressure in the head, says Lai, and your pediatrician will want to evaluate it to make sure there isn’t extra fluid in the brain.
- Baby is fussy and there are soft spot changes. “If baby is sick and not doing well, and there are soft spot changes, that’s when it’s time to bring this to the doctor’s attention,” Fisher says.
- Baby’s soft spot was accidentally pushed or hit. For the most part, this shouldn’t pose a problem, but if baby becomes inconsolable afterward or their behavior changes and becomes unusual, you’ll want to immediately call your pediatrician, Mustaleski notes.
Frequently Asked Questions
Can you touch the soft spot on baby’s head?
It’s understandable to be nervous about touching the soft spot on a baby’s head. “It’s literally a window to the brain, so we want to be gentle,” Fisher says. But that doesn’t mean you can’t touch baby’s head at all: You can do things like wash baby’s head and brush their hair—just have a light touch. “You want to avoid anything that directly impacts the head because it’s a more vulnerable area,” she says.
Why is the soft spot on baby’s head pulsing?
Experts stress that you shouldn’t panic if you notice that baby’s soft spot appears to be pulsing. “It’s [baby’s] pulse,” says Lai. Fisher notes that if baby otherwise seems healthy, this is a “completely normal” phenomenon. “The brain has pressure in it,” she explains. “Sometimes you can see these pulsations.”
How long do babies have soft spots?
Babies usually have soft spots until around 18 months old, at which point “all of the baby’s skull bones are generally joined together and the fontanelles are closed,” Mustaleski explains.
When does the anterior fontanelle close?
According to Lai, the anterior fontanelle should close by the time baby is 18 months old.
When does the posterior fontanelle close?
The posterior fontanelle should close by the time baby is 2 to 3 months old, per Lai.
What happens if a baby’s soft spot is hit or pushed on?
If baby’s fontanelles are accidentally hit or pushed on, monitor them to see if your child’s behavior changes afterward. If they’re “inconsolable or acting abnormally” immediately flag it to your pediatrician, as it could indicate a problem, Mustaleski says.
In general, there’s no need to stress about the soft spots on baby’s head. But if something seems off, it’s never a bad idea to tell your pediatrician.
Please note: The Bump and the materials and information it contains are not intended to, and do not constitute, medical or other health advice or diagnosis and should not be used as such. You should always consult with a qualified physician or health professional about your specific circumstances.
Plus, more from The Bump:
Danelle Fisher, MD, FAAP, is a pediatrician and vice chair of pediatrics at Providence Saint John’s Health Center in Los Angeles, California. She earned her medical degree at the Albert Einstein College of Medicine of Yeshiva University.
Naline Lai, MD, FAAP, is a pediatrician at Children’s Hospital of Philadelphia. She earned her medical degree from the University of Pittsburgh School of Medicine and completed her pediatric residency at The Children's Hospital of Philadelphia.
Rebekah Mustaleski, CPM-TN, IBCLC, is a certified professional midwife specializing in evidence-based maternity care. She co-founded Roots & Wings Midwifery in Knoxville, Tennessee. Mustaleski received her bachelor’s degree in psychology from Centre College and worked as a doula and birth photographer prior to establishing Roots & Wings.
Healthy Children (American Academy of Pediatrics), Your Baby’s Head, December 2021
Stat Pearls, Anatomy, Head and Neck: Fontanelles, July 2023
Centers for Disease Control and Prevention, Craniosynostosis, December 2024
Children’s Hospital Colorado, Achondroplasia
American Academy of Pediatrics, American Academy of Pediatrics Updates Safe Sleep Recommendations: Back is Best, June 2022
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