It’s 2 a.m. You’re rocking your newborn in the dark, and your hand drifts across the top of their head. There’s a spot that feels different. It’s soft, a little springy, and you swear it’s moving up and down.

Many new parents freeze right there. Is that normal? Did I press too hard? Should it be doing that?

Take a breath. What you’re feeling is a fontanelle on your baby’s head, and it’s completely normal. In fact, it’s one of the smartest design features of the human body. This guide explains what these baby soft spots are, why they’re there, how to check them, and when to call a doctor. We’ll keep the language plain and the steps simple, so you can feel confident the next time your hand finds that spot.

Baby Soft Spot Basics: What Is a Fontanelle on Baby’s Head?

A fontanelle is a gap in your baby’s skull where the bones haven’t joined together yet. People call it a soft spot. That nickname is a little misleading, though.

The area isn’t squishy like a sponge. It’s covered by a tough, strong membrane under the skin. It only feels soft compared to the hard bone around it. A healthy fontanelle feels slightly curved inward and firm when you touch it gently.

Think of it like the skin on a drum. It looks delicate, but it handles normal touch just fine.

Here’s the short version of what you need to know:

• Every baby has fontanelles, whether they were born vaginally or by C-section.
• Babies have two main ones, a bigger one on top and a smaller one at the back.
• They close on their own over time.
• Their look and feel can tell you useful things about your baby’s health.

Anterior Fontanelle and Posterior Fontanelle: Where Are They and What Do They Look Like? Fontanelle on Baby’s Head

Let’s look at each one so you know what you’re feeling.

The Anterior Fontanelle (Top of the Head) Fontanelle on Baby’s Head:

The anterior fontanelle is the big one. You’ll find it on the top front of your baby’s head. It’s usually diamond-shaped, and it’s the one most people mean when they say “baby’s soft spot.”

According to Cleveland Clinic, it averages about 2.1 centimeters across, roughly the size of a penny. Every baby is different, though. Some are a bit bigger and some a bit smaller.

The Posterior Fontanelle (Back of the Head)

The posterior fontanelle is smaller. It sits toward the back of the head and looks more triangular. It’s about the size of a pencil eraser, around half a centimeter. Many parents never notice it, because it closes early.

A Simple Way to Picture It

Imagine your baby’s skull as a set of puzzle pieces that haven’t snapped together yet. Where several pieces meet, there are small gaps. Those gaps are the fontanelles. Over time, the pieces grow toward each other and lock into place.

Fontanelle Purpose: Why Do Babies Have Soft Spots? Fontanelle on Baby’s Head

Nature didn’t make a mistake here. Soft spots do two big jobs.

Job 1: Helping Your Baby Be Born

During birth, your baby’s head has to pass through a narrow space. Because the skull plates aren’t fused, they can squeeze together and even overlap a little. This is why many babies born vaginally have a slightly cone-shaped head at first. It’s called molding, and it’s temporary. The bones settle back into place after birth.

A rigid, fully formed skull would make delivery much harder.

Job 2: Making Room for a Fast-Growing Brain

Your baby’s brain grows quickly in the first year of life. Flexible skull plates and open soft spots give it room to grow. Without that flexibility, the skull would limit the brain’s growth.

Normal Fontanelle Appearance: What a Healthy Soft Spot Looks and Feels Like Fontanelle on Baby’s Head

Before you can spot a problem, you need to know what “normal” looks like. Here’s your baseline.

A healthy fontanelle usually:

• Feels soft and flat, or very slightly curved inward
• Sits level with the rest of the head
• May show a light pulse that matches your baby’s heartbeat
• Looks a bit fuller when your baby cries, lies down, or vomits, then goes back to normal when they’re calm and upright

That last point matters. UPMC explains that a soft spot can bulge slightly when a baby is lying down, crying, or vomiting. It should return to normal once the baby is calm and held upright. This is why you should check the soft spot when your baby is quiet and upright, not mid-meltdown.

Touching Baby’s Soft Spot: Is It Safe to Touch a Fontanelle?

This is the question that worries parents most. The honest answer is yes, it’s safe to touch, as long as you’re gentle and use normal baby care.

Both UPMC and Cleveland Clinic say the membrane over the soft spot is tough. A minor bump is unlikely to hurt it. You don’t need to tiptoe around your baby’s head or avoid washing it.

That doesn’t mean you should be careless. You should always protect your baby from falls and hard knocks. But the fontanelle isn’t as fragile as it feels.

What You Can Do Without Worry

• Hold and cradle your baby’s head
• Gently wash their hair during bath time
• Put on soft hats and hoods
• Kiss the top of their head (yes, really)

Real-life scene: Think of a new mom named Aisha who avoided washing her son’s scalp for days because she was afraid of “hurting the soft spot.” By the time she asked her nurse about it, he had a patch of dry, flaky skin on his head. The nurse showed her how to wash his scalp using gentle, normal touch, and explained that the soft spot was tougher than it felt. Aisha says it was like a weight lifted. Many parents share this same fear, and it’s very fixable.

Step-by-Step: How to Check Your Baby’s Fontanelle at Home

You don’t need special tools. A calm baby and clean hands are enough. Follow these steps.

Step 1: Pick the right moment.
Wait until your baby is calm and awake, or sleeping peacefully. A crying baby’s soft spot can look fuller, which can fool you.

Step 2: Hold your baby upright.
Gently hold your baby in a sitting or upright position, supporting their head and neck. This is the position where a normal soft spot should look flat.

Step 3: Look first.
Look at the top of the head in good light. Is the spot flat, sunken, or puffed out? A flat or barely curved-in look is normal.

Step 4: Touch lightly.
Rest your fingertips softly on the spot. You’re not pressing. You’re just feeling. It should feel soft and flat, a bit like the area under your chin.

Step 5: Notice the pulse.
A light pulse is okay. It’s blood moving under the skin.

Step 6: Check the rest of your baby, too.
The soft spot is only one clue. Look at diapers, feeding, energy level, and mood. Doctors look at the whole picture, and so should you.

Step 7: Write down anything unusual.
If something looks different, jot down what you saw and when. Note any fever, vomiting, or sleepiness. This helps your doctor a lot.

Cleveland Clinic pediatrician Dr. Brigitta Moresea describes the soft spots as being like “automatic pressure sensors” that can give hints about hydration and brain status. That’s a helpful way to think about them. They’re one useful signal among many.

Sunken Fontanelle: A Common Sign of Dehydration

A sunken fontanelle is one that dips inward noticeably. Cleveland Clinic compares it to the divot on top of a golf tee. A normal soft spot is flat or only very slightly curved in.

What Does a Sunken Soft Spot Mean?

Most often, it points to dehydration. That means your baby isn’t getting enough fluids. It can happen when a baby is sick and isn’t feeding well, or when they’re losing fluids through vomiting or diarrhea.

Other Signs of Dehydration in Babies

A sunken soft spot usually isn’t the only clue. UPMC and Cleveland Clinic list other signs, including:

• Fewer wet diapers than usual (UPMC says fewer than six wet diapers a day is a warning sign)
• Dry mouth or lips
• Few or no tears when crying
• Extra sleepiness or extreme fussiness
• Sunken eyes
• Cool hands and feet
• Floppy arms and legs
• Refusing the breast or bottle
• Vomiting or diarrhea

What to Do: Step by Step, Fontanelle on Baby’s Head:

1. Look for other signs. Check diapers, lips, and energy.
2. Offer feeds. Cleveland Clinic suggests offering extra bottles or breastfeeding sessions.
3. Watch closely. See if the soft spot returns to normal as your baby drinks.
4. Call your pediatrician if the sunken look continues and your baby won’t take fluids, or if there are other signs of illness such as a worrying fever.

Real-life scene: Imagine a mom named Elena whose four-month-old had a stomach bug. On the second day, she noticed his soft spot looked lower than usual, and his diapers were far fewer. She remembered reading that this combo can mean dehydration, so she called the pediatric office instead of waiting. Because she acted early, the doctor could guide her right away. The lesson isn’t to panic. It’s to treat these clues as a reason to call.

Bulging Fontanelle: When a Swollen Soft Spot Needs Attention

A bulging fontanelle is one that looks puffed up or swollen. This one deserves a bit more attention than a sunken spot.

When Bulging Is Normal

Remember, a slightly fuller soft spot can be normal when your baby is crying, lying down, or vomiting. If it settles back down when your baby is calm and upright, that’s usually fine.

When Bulging Is a Warning Sign

If the soft spot keeps bulging while your baby is upright and calm, that’s a reason to call your doctor. UPMC and Cleveland Clinic both explain that a bulging soft spot can be linked to a range of causes. These include:

• Infection, such as meningitis or encephalitis
• Hydrocephalus, a buildup of fluid in the brain
• Head injury or bleeding
• A brain abscess
• In rare cases, a tumor or mass causing pressure

Please don’t read that list and panic. These causes are uncommon, and they come with other symptoms. But a bulging soft spot is the body’s way of raising a hand and saying, “Someone should look at this.”

What to Do: Step by Step

1. Check the timing. Is your baby calm and upright? Does the bulge stay?
2. Think about recent events. Did your baby fall or hit their head?
3. Look for other symptoms. Fever, vomiting, unusual sleepiness, or major changes in mood.
4. Call your child’s healthcare provider if the soft spot looks swollen.
5. Go to the emergency room if the swelling follows an injury, or if it comes with fatigue, vomiting, fever, or big changes in behavior.

UPMC says to call the doctor immediately if the soft spot looks unusually swollen and your baby has a fever or seems lethargic.

When Does the Fontanelle Close? Soft Spot Timeline by Age

This is one of the top questions parents ask. The honest answer is that there’s a range, and sources give slightly different numbers. Here’s what the two major health systems say.

Posterior Fontanelle (Back)

• UPMC: closes about 6 to 8 weeks after birth
• Cleveland Clinic: closes by around 2 to 3 months

So, in general, expect it to close in the first couple of months.

Anterior Fontanelle (Top)

• UPMC: usually closes between 13 and 24 months
• Cleveland Clinic: typically closes soon after the first birthday

Put together, most babies’ top soft spot closes sometime between about 1 and 2 years old.

A Quick Timeline

Age	What’s Usually Happening
Birth	Both soft spots are open
6 weeks to 3 months	Back (posterior) soft spot closes
3 to 12 months	Top (anterior) soft spot slowly gets smaller as the skull grows
About 12 to 24 months	Top soft spot closes

Why Closing Time Varies

Just like walking and talking, babies close their soft spots on their own schedule. A slightly slower or faster timeline isn’t automatically a problem. Your doctor checks this at routine visits and will tell you if anything needs a closer look.

Soft Spot Closed Too Early: Craniosynostosis and the “Quiet” Fontanelle

Some parents worry the opposite way. They can’t feel the soft spot and wonder if it closed too soon.

The “Quiet” Fontanelle

Cleveland Clinic’s Dr. Moresea describes a “quiet fontanelle”, which is a soft spot that’s just less noticeable. If your baby’s head is growing normally, that usually isn’t a concern.

What Is Craniosynostosis?

Occasionally, skull bones close earlier than normal. This condition is called craniosynostosis. Depending on which bones fuse early, a baby’s head may develop an uneven or unusual shape. The most common type, sagittal craniosynostosis, creates a longer head shaped a bit like a football.

What Can Happen Next

If a provider suspects early closing, they may suggest an imaging test to check. Some children with craniosynostosis need a special helmet to help reshape the skull. Some need surgery. Your care team will guide you through the options.

Your Step-by-Step Response

1. Notice if your baby’s head shape looks uneven.
2. Mention it at your next visit, or call sooner if you’re worried.
3. Don’t try to “fix” it yourself.
4. Follow your provider’s advice on tests and next steps.

Soft Spot That Won’t Close: Large or Late-Closing Fontanelles

Now the other direction. What if the soft spot seems big or stays open past the usual time?

Cleveland Clinic says soft spots that are larger than average, or that stay open longer than about a year, can sometimes be linked to certain medical conditions. UPMC and Cleveland Clinic mention possibilities such as:

• Down syndrome
• Achondroplasia, a growth condition
• Congenital hypothyroidism
• Rickets, a condition that weakens bones
• Unusually high pressure in the brain

This list sounds scary, but here’s the key point both sources stress. These conditions come with other symptoms. A late-closing soft spot by itself, in a baby who’s otherwise growing and developing well, usually just means a slower timeline. Researchers have also written about this topic in a medical reference on large fontanelles, if you’d like to read further.

If your baby’s soft spot seems to be taking a long time, bring it up at your next checkup. Your doctor will look at the whole picture.

Everyday Baby Care and the Fontanelle: Bathing, Hats, and Sleep

Let’s turn all this knowledge into daily habits.

Bath Time

You can wash your baby’s head gently. Use a soft washcloth or your hand, a little water, and normal caution. If you want a full walkthrough, UPMC has a helpful guide on how to bathe a newborn.

Hats and Hoods

Soft hats are fine. There’s no need to avoid them because of the soft spot.

Holding and Carrying

Always support your baby’s head and neck, especially in the early months. That’s good practice for the whole body, not just the soft spot.

If Your Baby Hits Their Head

Accidents happen. A tiny bump during normal handling is unlikely to cause harm to the soft spot. But a real fall is different. Cleveland Clinic notes that a swollen soft spot after a fall can be a sign of head trauma, sometimes with vomiting. In that case, get prompt medical attention.

Sleep and Safety

Following safe sleep practices matters for every baby. Cleveland Clinic has a useful article on reducing SIDS risk.

Fontanelle Checks at Well-Baby Visits: What Doctors Do

You don’t have to be the only one watching. At routine well-child checkups, your baby’s provider will usually:

• Measure your baby’s head size
• Gently feel the soft spots
• Compare growth to what’s expected for your baby’s age
• Ask about feeding, diapers, and development

This is a great time to ask questions. Bring a short list. Parents often forget things in the moment, so jot them on your phone.

UPMC puts it simply: your doctor checks your baby’s soft spot for proper growth as part of a routine well visit. So keeping those appointments is one of the best things you can do.

Quick Reference: Fontanelle Warning Signs at a Glance

What You See	What It May Mean	What to Do
Flat or slightly curved in, light pulse	Normal	Nothing needed
Slightly full while crying or lying down, flat again when calm and upright	Usually normal	Keep watching
Clearly sunken	Possible dehydration	Offer fluids, look for other signs, call your provider if it continues
Keeps bulging when calm and upright	Needs medical review	Call your provider
Bulging with fever, vomiting, or unusual sleepiness	Possibly serious	Seek urgent or emergency care
Swelling after a head injury	Possible head trauma	Seek prompt medical care
Hard to feel, or head shape looks uneven	Possible early closing	Talk to your provider
Still open well past the first year	Often a slower timeline, sometimes a sign of another condition	Discuss at your next visit

Final Thoughts: You Know Your Baby Best

Let’s bring it all together. The fontanelle on your baby’s head is a normal, helpful part of early growth. It helps your baby’s head fit through the birth canal. It gives the brain room to grow. And it gives you and your doctor a simple way to spot certain problems early.

Here’s what to remember:

• Normal is flat, soft, and maybe a little pulsey.
• Sunken often means dehydration. Offer fluids and call if it continues.
• Bulging that stays when your baby is calm and upright needs a doctor’s attention.
• Soft spots close on their own schedule, usually between the first and second birthday for the top one.
• Gentle touch is safe. You can wash, hold, and cuddle your baby with confidence.
• Trust your instincts. UPMC reminds parents that you know your child and their habits best. When in doubt, call.

You don’t need to be a doctor to care for your baby well. You just need good information, a calm approach, and the courage to ask questions. You now have all three.

Where to Get Trusted Help

• Your baby’s pediatrician or family doctor is your first call for any worry about the soft spot.
• Emergency services are for urgent situations such as a bulging soft spot with fever, extreme sleepiness, or a head injury.
• If you’re in Australia, Pregnancy, Birth and Baby offers a free call line with maternal child health nurses (1800 882 436), open 7am to midnight AET, seven days a week. It also has a video call option and a health service finder.
• For deeper reading, see UPMC’s guide to fontanelles and Cleveland Clinic’s soft spot article.

The next time your hand finds that soft spot at 2 a.m., you’ll know exactly what you’re feeling, and you’ll feel steady, not scared.

Fontanelle FAQs: Quick Answers for Worried Parents