Medical Disclaimer This article is for educational purposes only and does not replace medical advice, diagnosis, or treatment. Every baby’s head shape, head growth, and fontanelle timing should be interpreted in context by a qualified healthcare professional. Always talk with your child’s pediatrician, craniofacial team, pediatric neurosurgeon, or healthcare provider about your child’s individual situation.
Before parents can understand craniosynostosis, it helps to understand how a baby’s skull is supposed to grow.
A baby’s skull is not one solid piece of bone.
It is made of several bony plates connected by flexible seams called sutures. These sutures allow the skull to expand as the brain grows. Where some of these sutures meet, there are wider soft spaces called fontanelles, often called “soft spots.”
Parents often ask:
- What are skull sutures?
- What are soft spots?
- Is it safe to touch the soft spot?
- When should the soft spot close?
- Does a closed soft spot mean craniosynostosis?
- Why is my newborn’s head cone-shaped?
- Why is one side of my baby’s head flat?
- How do doctors know whether head shape is normal?
- How does skull growth relate to brain growth?
The quick answer is:
A baby’s skull is designed to be flexible early in life. Sutures and fontanelles help the skull change shape during birth and expand as the brain grows. A soft spot closing is not the same thing as skull sutures fusing too early. Head shape, head growth, and the overall exam matter more than one finding by itself.
Mayo Clinic explains that a baby’s skull is made of small plates of bone connected by flexible, fibrous joints called sutures, and these sutures allow the skull to get bigger as the brain grows. The sutures meet at the fontanelles, or soft spots. (Mayo Clinic)
This foundation matters because craniosynostosis happens when one or more of those sutures closes too early. When that happens, the skull may stop growing normally in that direction and grow more in other directions, creating a head shape that can look long, narrow, triangular, flat, wide, or asymmetric. (CDC)
This guide explains normal skull growth first, so the later craniosynostosis topics are easier to understand.
Quick Answer: What Are Skull Sutures and Soft Spots?
Skull sutures are flexible seams between the bones of a baby’s skull.
Fontanelles , or soft spots, are wider spaces where sutures meet.
These structures matter because they allow:
- The skull to mold during birth
- The brain to grow rapidly in infancy
- The head to expand over time
- Healthcare providers to assess head growth and, sometimes, pressure concerns
The American Academy of Pediatrics describes the skull as a complex structure that must protect the brain and sensory organs while still allowing growth during development. The AAP also explains that sutures are fibrous joints that allow temporary skull deformation during birth and allow growth along the edges of skull bones until they fuse later in life. (American Academy of Pediatrics)
The patient-friendly takeaway:
Sutures and soft spots are not defects. They are normal parts of a baby’s skull.
Why a Baby’s Skull Is Not One Solid Bone
A newborn’s brain grows quickly. If the skull were one solid, rigid shell at birth, it would not be able to expand properly.
Instead, a baby’s skull is made of several bones that fit together like flexible puzzle pieces.
The main skull bones parents may hear about include:
Frontal bones These form the forehead area.
Parietal bones These form much of the top and sides of the skull.
Occipital bone This forms the back of the skull.
Temporal bones These are on the sides of the skull near the ears.
The AAP describes the cranial vault as being made of paired frontal, parietal, and temporal bones, along with a single occipital bone. These bones are separated by sutures such as the metopic, sagittal, coronal, squamosal, and lambdoid sutures. (American Academy of Pediatrics)
A simple way to think about it:
- The brain is growing.
- The skull bones are expanding around it.
- The sutures are the growth seams that make that expansion possible.
What Are Cranial Sutures?
Cranial sutures are the flexible seams between skull bones.
They are not empty cracks. They are living, fibrous joints that help the skull grow in a controlled way.
The main sutures parents usually hear about are:
Suture
Where it is
Why parents may hear about it
Sagittal suture
Runs from front to back along the top middle of the head
Early closure can cause a long, narrow head shape
Metopic suture
Runs from the top of the nose up the middle of the forehead
Early closure can cause a triangular forehead
Coronal sutures
Run from each ear area toward the top/front of the skull
Early closure can cause forehead, eye, or facial asymmetry
Lambdoid sutures
Run along the back of the skull
Early closure can cause back-of-head flattening and can be confused with positional plagiocephaly
Squamosal sutures
Located on the sides of the skull near the temporal bones
Less commonly discussed in basic parent education but part of normal skull anatomy
Mayo Clinic describes the sagittal, coronal, metopic, and lambdoid sutures and explains that the type of craniosynostosis depends on which suture closes too early. (Mayo Clinic)
The practical message:
The suture involved helps explain the head shape. That is why craniofacial teams look at the head from the front, side, back, and top.
What Do Sutures Actually Do?
Sutures have several important jobs.
1. They help the skull mold during birth
During vaginal delivery, a baby’s skull may temporarily change shape as the head passes through the birth canal. This is called molding.
HealthyChildren.org, from the American Academy of Pediatrics, explains that a baby’s skull has soft bony plates that can compress and overlap during birth, which is why some newborns are born with a cone-shaped or slightly misshapen head. (HealthyChildren.org)
MedlinePlus similarly explains that the bones of a newborn skull are soft and flexible, with gaps between the plates, and that pressure during birth can mold the head into an oblong shape. (MedlinePlus)
The parent-friendly takeaway:
A cone-shaped newborn head can be normal after birth, especially after vaginal delivery. It often improves as swelling and molding resolve.
2. They let the skull expand as the brain grows
The brain grows rapidly during infancy. Sutures allow the skull to expand with that growth.
Mayo Clinic explains that sutures remain flexible during infancy so the skull can grow as the brain grows. (Mayo Clinic)
The AAP explains that sutures allow growth along the edges of skull bones until they ossify and fuse later in life. (American Academy of Pediatrics)
The practical message:
Sutures are growth zones. They help the skull keep up with the brain.
3. They influence head shape
Head shape is not random. It reflects how the skull bones grow in relation to the sutures.
If sutures are open and the baby’s brain and skull are growing normally, the head usually grows in a balanced way.
If outside pressure affects the skull, such as a baby resting mostly on one side, the head may become flat in that area.
If a suture closes too early, skull growth is restricted across that suture and redirected toward other open sutures.
The AAP explains that when sutures close abnormally, growth is prevented at the fused suture and redirected to other open sutures, which changes skull shape in predictable ways. (American Academy of Pediatrics)
The takeaway:
Head shape gives clues, but it must be interpreted by someone who understands normal growth, positional flattening, and craniosynostosis patterns.
What Are Fontanelles?
Fontanelles are the soft spaces where skull bones and sutures meet.
Most parents hear about two main fontanelles:
Anterior fontanelle The larger soft spot near the top/front of the head.
Posterior fontanelle The smaller soft spot near the back of the head.
The AAP explains that the anterior fontanelle forms where the paired frontal and parietal bones meet, while the posterior fontanelle forms where the paired parietal bones meet the occipital bone. (American Academy of Pediatrics)
Stanford Medicine Children’s Health explains that fontanelles are spaces between skull bones where sutures intersect, and that these spaces are covered by tough membranes that protect the brain and underlying tissues. (Stanford Children's Health)
The patient-friendly explanation:
A soft spot is not an open hole into the brain. It is a normal space covered by protective tissue.
Is It Safe to Touch the Soft Spot?
Yes, gentle normal touch is usually safe.
Many parents are afraid to wash, brush, or lightly touch the soft spot. That fear is understandable, but the soft spot is protected by tough tissue.
HealthyChildren.org explains that soft spots are well protected from typical day-to-day baby handling, despite not having a bony layer directly over them. (HealthyChildren.org)
Children’s Hospital Colorado also says it is okay to lightly touch a baby’s fontanelles and that a healthy fontanelle should feel soft and flat. (Children's Hospital Colorado)
The practical message:
You do not need to press on the soft spot, but normal gentle washing, touching, and handling are okay.
What Should a Normal Soft Spot Feel Like?
A normal fontanelle often feels:
- Soft
- Flat
- Slightly curved inward or level with the skull
- Different in size from baby to baby
- Easier to feel when the baby is calm and upright
- Harder to feel as the baby gets older
Children’s Hospital Colorado says a healthy fontanelle should feel soft and flat, and that bulging or sinking can be a sign of a health concern. (Children's Hospital Colorado)
HealthyChildren.org also notes that a soft spot may appear to pulsate, which is usually normal and reflects visible pulsing that corresponds with the baby’s heartbeat. (HealthyChildren.org)
The parent-friendly takeaway:
Soft, flat, and sometimes gently pulsing can be normal. Persistently bulging, very sunken, or associated with illness should be discussed with a doctor.
When Do Fontanelles Close?
Fontanelle closure varies.
Parents often panic when someone says, “The soft spot feels small,” or “I cannot feel the soft spot anymore.” But timing is not the same for every baby.
The AAP explains that the anterior fontanelle most commonly closes around 12 months, but there is wide normal variation, with closure reported between 4 and 26 months. The AAP also emphasizes that fontanelle closure does not mean the sutures are closed and does not mean skull growth has stopped. (American Academy of Pediatrics)
Children’s Hospital Colorado gives a parent-facing range: the posterior fontanelle usually closes first, often within 2 months of birth, while the anterior fontanelle commonly closes between 7 and 18 months. (Children's Hospital Colorado)
A helpful way to explain it:
Fontanelle
Location
Typical parent-level timing
Posterior fontanelle
Back of the head
Usually closes first, often in the first couple months
Anterior fontanelle
Top/front of the head
Often closes during the first 1–2 years, with wide normal variation
The key point:
A soft spot that seems small or closed is not enough by itself to diagnose craniosynostosis. Head shape and head growth matter.
Soft Spot Closure Is Not the Same as Suture Closure
This is one of the most important things for parents to understand.
The soft spot is a space where skull bones meet. As the bones grow closer together, that space may become harder to feel.
But that does not automatically mean the skull sutures have fused too early.
The AAP states that closure of the fontanelle does not mean the sutures are closed or that further skull growth is not possible. It also says that as long as head growth is appropriate on the normal growth curve and head shape is normal, there should not be concern for craniosynostosis based on fontanelle closure alone. (American Academy of Pediatrics)
The patient-friendly takeaway:
A closed or hard-to-feel soft spot does not automatically mean craniosynostosis. Doctors look at head shape, head circumference, growth pattern, and exam findings together.
How the Brain Helps Shape the Skull
The skull grows because the brain is growing.
As the brain expands, the skull bones grow outward along their edges. The sutures allow those bone edges to keep growing without fusing too soon.
The AAP explains that differentiating bone-forming cells accumulate on the leading edges of cranial vault bones as the brain expands during prenatal and early postnatal growth. (American Academy of Pediatrics)
Mayo Clinic explains the same idea in simpler terms: the sutures allow a baby’s skull to get bigger as the brain grows. (Mayo Clinic)
The simple version:
Brain growth is the engine. Skull sutures are the expansion seams.
What Happens If a Suture Closes Too Early?
When a suture closes too early, the skull cannot grow normally across that suture.
The brain still grows. The skull then grows more in directions where sutures remain open.
The CDC explains that when a suture closes, the baby’s head stops growing only in that part of the skull, while areas with open sutures continue to grow. This can lead to an abnormal skull shape. (CDC)
Mayo Clinic similarly explains that brain growth continues even when one or more sutures close too early, and open sutures on other sides of the head allow growth in those directions, causing an atypical head shape. (Mayo Clinic)
A simple example:
- If the sagittal suture closes too early, the skull may not widen normally from side to side.
- The brain still grows, so the head may grow longer from front to back.
- That can create the long, narrow head shape associated with sagittal craniosynostosis.
The practical message:
Craniosynostosis is not just “a funny head shape.” It is a growth-pattern problem caused by early suture fusion.
Why Newborn Heads Can Look Misshapen at First
Not every unusual head shape means craniosynostosis.
Many newborns have temporary molding from delivery.
HealthyChildren.org explains that slightly misshapen heads are common right after birth and that the skull bones often round out over the next several weeks. (HealthyChildren.org)
MedlinePlus explains that pressure in the birth canal can mold the newborn head and that the skull bones may even overlap depending on the amount and length of pressure. (MedlinePlus)
Normal newborn molding may include:
- A cone-shaped head
- Temporary ridges from overlapping bones
- Mild swelling
- A head shape that changes during the first days or weeks
The patient-friendly takeaway:
A newborn head can look unusual at first and still be normal. What matters is whether the shape improves, stays the same, or becomes more concerning over time.
What Is Positional Head Shape Change?
A baby’s skull is flexible, which is good for brain growth. But that flexibility also means head shape can be affected by repeated pressure.
For example, if a baby often rests with the head turned to the same side, that side may flatten. This is often called positional plagiocephaly or deformational plagiocephaly.
This is different from craniosynostosis.
In positional plagiocephaly, the sutures are not fused too early. The skull shape is molded by outside pressure.
In craniosynostosis, the skull shape changes because a suture closed too early.
The AAP clinical report focuses on helping clinicians distinguish head-shape abnormalities caused by synostotic processes, meaning fused sutures, from deformational and other nonoperative head-shape changes. (American Academy of Pediatrics)
HealthyChildren.org explains that babies can develop a flat spot from spending too much time with the head in one position, and it recommends supervised tummy time while awake along with continued back sleeping for safety. (HealthyChildren.org)
The key point:
A baby’s skull can change shape from pressure even when the sutures are normal and open.
Back to Sleep, Tummy to Play
Parents sometimes worry that safe sleep recommendations caused their baby’s flat spot.
It is true that back sleeping can contribute to positional flattening in some babies, but back sleeping remains the safest sleep position for healthy babies.
HealthyChildren.org states that healthy babies are safest sleeping on their backs for nighttime sleep and naps, and that side sleeping is not as safe and is not advised. It also recommends tummy time only when babies are awake and being watched. (HealthyChildren.org)
Ways to reduce positional pressure while still following safe sleep guidance include:
- Supervised tummy time while awake
- Holding the baby when awake
- Changing the direction the baby faces in the crib
- Alternating sides during bottle feeding
- Limiting long periods in swings, bouncy seats, and car seats when not needed for travel
- Addressing torticollis or a strong head-turning preference
HealthyChildren.org recommends starting tummy time with short sessions, such as 3 to 5 minutes 2 to 3 times per day, and working up as the baby gets stronger. (HealthyChildren.org)
The practical message:
Back to sleep protects babies during sleep. Tummy to play helps strength, development, and pressure relief while awake and supervised.
How Doctors Track Head Growth
One of the most important parts of infant care is tracking growth over time.
At well-child visits, healthcare providers usually measure:
- Weight
- Length
- Head circumference
Head circumference is the measurement around the largest part of the baby’s head. It helps doctors see whether the head is growing along an expected pattern.
The CDC explains that growth charts are percentile curves used by pediatricians, nurses, and parents to track selected body measurements in infants, children, and adolescents. The CDC also notes that growth charts are not meant to be used as the only diagnostic tool; they contribute to the overall health picture. (CDC)
For craniosynostosis concerns, doctors may look at:
- Whether head circumference is increasing over time
- Whether the baby is staying on a growth curve
- Whether head growth has slowed
- Whether head shape matches the growth pattern
- Whether development is on track
The patient-friendly takeaway:
One head measurement matters less than the pattern over time.
What Is Normal Variation?
Babies do not all have identical head shapes.
Some normal differences may include:
- A slightly elongated head after birth
- A mild ridge from newborn molding
- A soft spot that feels smaller than expected
- A head shape that resembles a parent’s head shape
- A mild flat spot that improves with repositioning
- A head circumference that is small or large but follows a steady curve
The AAP notes that pediatric providers see many head shapes, including craniosynostosis, other craniofacial disorders, deformational conditions, and normal variants. (American Academy of Pediatrics)
The reassuring message:
Variation is common. The goal is not to make every baby’s head perfectly round. The goal is to recognize which patterns need treatment or specialist evaluation.
What Is Not Normal or Should Be Checked?
Parents should ask their pediatrician about head shape if they notice:
- A head shape that is becoming more unusual over time
- A long, narrow head shape
- A triangular forehead
- One forehead side flatter than the other
- One eye or eyebrow looking higher or different
- A hard ridge that persists along a suture
- Back-of-head flattening that does not improve
- One ear appearing shifted compared with the other
- A strong preference for turning the head one direction
- Limited neck motion or suspected torticollis
- A soft spot that seems persistently bulging or very sunken
- Head growth that slows, crosses percentiles, or seems off track
- Developmental delays or regression
Mayo Clinic lists possible craniosynostosis symptoms as an atypical skull shape, imbalance of facial features or ears, and a raised hard ridge along the closed suture. (Mayo Clinic)
Johns Hopkins notes that trained craniofacial surgeons and neurosurgeons can distinguish craniosynostosis from other causes of head-shape differences, and that diagnosis may include history, physical exam, head circumference measurement, and imaging if needed. (Hopkins Medicine)
The practical message:
You do not need to diagnose the problem yourself. You only need to notice when the pattern deserves a professional look.
When a Soft Spot May Need Medical Attention
A soft spot can change slightly with position, crying, or hydration, but certain findings should be discussed promptly.
Call your child’s healthcare professional if the fontanelle seems:
- Persistently bulging
- Very sunken, especially with poor feeding or fewer wet diapers
- Associated with fever, vomiting, unusual sleepiness, or irritability
- Associated with poor feeding
- Associated with developmental regression or decreased alertness
Children’s Hospital Colorado explains that a bulging or sunken fontanelle may be a sign of a health issue, and HealthyChildren.org notes that a sunken soft spot combined with poor feeding and dry diapers can suggest dehydration. (Children's Hospital Colorado)
Johns Hopkins lists signs that can be associated with elevated intracranial pressure in craniosynostosis, including a full or bulging fontanelle, decreased alertness, noticeable scalp veins, increased irritability, high-pitched cry, poor feeding, projectile vomiting, increasing head circumference, and developmental delays. (Hopkins Medicine)
The patient-friendly takeaway:
A soft spot should be interpreted with the baby’s overall behavior, feeding, hydration, head growth, and illness symptoms.
Why Head Shape Alone Can Be Confusing
The same general description can mean different things.
For example:
- “Flat spot” could mean positional plagiocephaly or, rarely, lambdoid craniosynostosis.
- “Forehead ridge” could be a normal metopic ridge or metopic craniosynostosis.
- “Small soft spot” could be normal variation or part of a broader concern.
- “Long head” could be newborn molding or sagittal craniosynostosis.
- This is why pediatricians and craniofacial teams examine more than one feature.
They may look at:
Top view of the head
Forehead shape
Back-of-head shape
Ear position
Eye and eyebrow symmetry
Jaw and facial symmetry
Suture ridges
Neck range of motion
Head circumference trend
Developmental milestones
Birth history
Family head shapes
The AAP clinical report was created to improve recognition and timely referral for craniosynostosis while also helping clinicians distinguish it from deformational and nonoperative head-shape changes. (American Academy of Pediatrics)
The practical message:
Parents often see “flat” or “ridge.” Specialists look for the full pattern.
How Normal Skull Growth Helps Explain Craniosynostosis
Now that normal skull growth is clearer, craniosynostosis becomes easier to understand.
In normal skull growth:
- Sutures remain open during infancy.
- The brain grows.
- The skull expands.
- Fontanelles gradually close.
- Head circumference follows a pattern.
- Head shape stays generally balanced or improves if mild molding was present.
In craniosynostosis:
- One or more sutures close too early.
- Growth is restricted near the fused suture.
- The skull grows more in other directions.
- Head shape changes in a predictable pattern.
- Some cases need surgery to create space and improve skull shape.
Mayo Clinic explains that brain growth continues even when one or more sutures close too early, and open sutures elsewhere allow growth in other directions, causing an atypical head shape. (Mayo Clinic)
The CDC explains that if more than one suture closes early, the brain may not have enough room to grow, which can lead to pressure inside the skull. (CDC)
The key takeaway:
Craniosynostosis is a problem of timing. Sutures are supposed to close eventually, but not too early and not in a way that restricts skull growth.
Common Parent Misunderstandings
“The soft spot closed, so my baby must have craniosynostosis.”
Not necessarily.
The AAP is clear that fontanelle closure does not mean sutures are closed, and it does not mean skull growth has stopped. If head shape and head growth are normal, early fontanelle closure alone should not automatically create concern for craniosynostosis. (American Academy of Pediatrics)
“I can feel a ridge, so the skull must be fused.”
Not always.
Some ridges can happen from birth molding, normal suture anatomy, or normal metopic ridge development. Persistent ridges should be checked, but a ridge alone is not enough to make the diagnosis.
“My baby’s head is flat, so it must be craniosynostosis.”
Usually, flat spots are positional, but craniosynostosis can sometimes cause flattening too. The pattern, ear position, facial symmetry, head growth, and exam help tell the difference.
“If the head circumference is normal, everything must be fine.”
Not always.
Head circumference is important, but it does not replace head-shape evaluation. A baby can have a head circumference that is still growing while the head shape is abnormal.
“If the head shape is unusual, my baby’s brain must be damaged.”
Not necessarily.
Many head-shape concerns are treatable, positional, or monitored. The reason for evaluation is to identify which babies need treatment and which babies can be safely reassured.
What Parents Can Do at Home
Parents cannot diagnose skull growth problems at home, but they can observe patterns and bring useful information to the pediatrician.
Helpful steps include:
- Take photos from the same angles every few weeks.
- Notice whether the shape is improving, worsening, or staying the same.
- Track whether your baby always turns the head to one side.
- Ask whether head circumference is following the growth curve.
- Ask whether the pediatrician feels any persistent suture ridges.
- Use supervised tummy time while awake.
- Continue safe sleep on the back.
Limit unnecessary time in car seats, swings, and bouncers when the baby is not sleeping or traveling.
Ask about physical therapy if your baby has torticollis or limited neck motion.
HealthyChildren.org recommends awake, supervised tummy time and position variation to reduce flat spots while maintaining safe back sleeping for naps and nighttime sleep. (HealthyChildren.org)
The practical message:
Parents do not have to solve the head-shape question alone. Good photos, growth tracking, and timely questions help the care team.
Bring these questions to your child’s appointment:
- Is my baby’s head circumference growing along the expected curve?
- Does my baby’s head shape look normal, positional, or concerning for craniosynostosis?
- Do you feel any ridges along the sutures?
- Is the soft spot size concerning in the context of head growth and head shape?
- Does my baby have torticollis or a head-turning preference?
- Would physical therapy help?
- Should we try repositioning and tummy time first?
- Should we be referred to a craniofacial team?
- Do we need imaging, or should a specialist evaluate first?
- What changes should make us call sooner?
The AAP emphasizes that pediatric providers should recognize abnormal head shapes caused by both craniosynostosis and deformational processes, and that the goal is timely referral while distinguishing surgical from non-surgical conditions. (American Academy of Pediatrics)
When to Ask About a Craniofacial Referral
Ask about referral if:
- The pediatrician suspects craniosynostosis.
- The head shape is worsening or not improving.
- There is a persistent ridge along a suture.
- The head shape looks long and narrow, triangular, asymmetric, or unusual.
- There is forehead, eye, brow, or ear asymmetry.
- The back-of-head flattening does not match typical positional plagiocephaly.
- Head growth is slowing or crossing percentiles.
- More than one suture may be involved.
- You feel uncertain and want specialist confirmation.
Johns Hopkins explains that trained craniofacial surgeons and neurosurgeons can tell the difference between craniosynostosis and other causes of head-shape differences. (Hopkins Medicine)
The patient-friendly takeaway:
A referral does not mean surgery is definite. It means the right experts can clarify what is happening.
Red Flags: Symptoms That Should Not Be Ignored
Call your child’s healthcare professional promptly if your baby has:
A persistently bulging soft spot
Repeated or projectile vomiting
Unusual sleepiness or decreased alertness
Poor feeding
High-pitched cry
Extreme irritability
Very noticeable scalp veins
Rapidly increasing head size
Head growth that slows or drops percentiles
Developmental delays or loss of skills
Seizure-like activity
Trouble breathing
A head shape that is rapidly becoming more unusual
Johns Hopkins lists several signs that may be associated with elevated intracranial pressure in craniosynostosis, including a full or bulging fontanelle, decreased alertness, scalp veins, irritability, high-pitched cry, poor feeding, projectile vomiting, increasing head circumference, and developmental delays. (Hopkins Medicine)
Seek urgent medical care if your baby is difficult to wake, has trouble breathing, has seizure-like activity, has repeated vomiting, or seems seriously ill.
How to Explain Baby Skull Growth to Family Members
Here is a simple explanation parents can use:
“A baby’s skull is not one solid bone. It is made of several plates connected by flexible seams called sutures. The soft spots are where some of those seams meet. These spaces help the skull mold during birth and grow as the brain grows. Soft spots close over time, but that does not automatically mean the skull sutures have fused too early. Doctors look at the whole pattern: head shape, head growth, soft spots, ridges, and development.”
This can help family members understand why a baby’s head can look different without every change being dangerous — and why some patterns still need evaluation.
- A baby’s skull is made of several bony plates, not one solid bone.
- Sutures are flexible seams between skull bones.
- Fontanelles, or soft spots, are wider spaces where sutures meet.
- Sutures and fontanelles help the skull mold during birth and expand as the brain grows.
The anterior fontanelle usually closes sometime during infancy or toddlerhood, with wide normal variation.
- Fontanelle closure is not the same as suture closure.
- A small or closed soft spot does not automatically mean craniosynostosis.
- Newborn molding can make the head look cone-shaped or ridged right after birth.
- Positional pressure can cause flat spots even when sutures are open.
- Head circumference trends matter more than one measurement.
Doctors evaluate head shape, growth curve, soft spots, ridges, facial symmetry, and development together.
Craniosynostosis happens when one or more sutures closes too early, changing skull growth patterns.
The most important message for parents is:
Sutures and soft spots are normal parts of infant skull growth. A baby’s head shape should be watched over time, and concerns should be discussed with a pediatrician or craniofacial specialist — but one soft spot, ridge, or flat area does not tell the whole story.
Frequently Asked Questions About Baby Skull Growth, Sutures, and Soft Spots
What are skull sutures?
Skull sutures are flexible seams between the bones of a baby’s skull. They allow the skull to mold during birth and expand as the brain grows. Mayo Clinic describes sutures as flexible, fibrous joints that connect the small plates of bone in a baby’s skull. (Mayo Clinic)
What are fontanelles?
Fontanelles are soft spaces where skull bones and sutures meet. Parents usually hear about the anterior fontanelle near the top/front of the head and the posterior fontanelle near the back of the head. The AAP describes the anterior and posterior fontanelles based on where the frontal, parietal, and occipital bones meet. (American Academy of Pediatrics)
Is the soft spot an opening to the brain?
No. The soft spot is a normal space between skull bones, but it is covered by protective tissue. Stanford Medicine Children’s Health explains that fontanelles are covered by tough membranes that protect the underlying soft tissues and brain. (Stanford Children's Health)
Is it safe to touch my baby’s soft spot?
Yes, gentle normal touch is usually safe. HealthyChildren.org explains that soft spots are well protected from typical day-to-day baby handling. (HealthyChildren.org)
Why does the soft spot pulse?
A soft spot may appear to pulse because of blood flow that matches the baby’s heartbeat. HealthyChildren.org notes that this visible pulsing is usually normal. (HealthyChildren.org)
When does the anterior soft spot close?
The timing varies widely. The AAP states that the anterior fontanelle most commonly closes around 12 months, but closure can vary from 4 to 26 months. (American Academy of Pediatrics)
When does the posterior soft spot close?
The posterior fontanelle usually closes earlier than the anterior fontanelle. Children’s Hospital Colorado says the posterior fontanelle usually closes within 2 months of birth. (Children's Hospital Colorado)
Does a closed soft spot mean craniosynostosis?
Not by itself. The AAP explains that closure of the fontanelle does not mean the sutures are closed and does not mean skull growth has stopped. If head growth and head shape are normal, early fontanelle closure alone should not automatically create concern for craniosynostosis. (American Academy of Pediatrics)
Why was my newborn’s head cone-shaped?
A cone-shaped newborn head can happen because the skull bones mold during birth. HealthyChildren.org explains that the soft bony plates of a baby’s skull can compress and overlap to fit through the birth canal. (HealthyChildren.org)
How long does newborn head molding last?
Many newborn head-shape changes improve over the first days to weeks. HealthyChildren.org says slightly misshapen heads are common right after birth and usually round out over the next several weeks. (HealthyChildren.org)
What is positional plagiocephaly?
Positional plagiocephaly is a head-shape change caused by repeated pressure on one area of the skull. It is different from craniosynostosis because the sutures are not fused too early. The AAP clinical report focuses on distinguishing deformational head-shape changes from craniosynostosis. (American Academy of Pediatrics)
Does back sleeping cause flat head?
Back sleeping can contribute to flat spots in some babies, but back sleeping remains the safest sleep position. HealthyChildren.org states that healthy babies are safest sleeping on their backs for nighttime sleep and naps. (HealthyChildren.org)
How can I reduce the chance of a flat spot?
Use supervised tummy time while your baby is awake, vary your baby’s position, limit unnecessary time in swings or car seats, and ask about physical therapy if your baby has a strong head-turning preference. HealthyChildren.org recommends tummy time while awake and watched, starting with short sessions and increasing as the baby grows stronger. (HealthyChildren.org)
What is head circumference?
Head circumference is the measurement around the largest part of a baby’s head. It helps healthcare providers track head growth over time. CDC explains that growth charts are percentile curves used to track selected body measurements in infants and children. (CDC)
Does a normal head circumference rule out craniosynostosis?
Not always. Head circumference is important, but doctors also look at head shape, suture ridges, facial symmetry, growth pattern, and development. Growth charts help form an overall health picture, but CDC notes they are not meant to be used as the only diagnostic tool. (CDC)
What happens if a skull suture closes too early?
If a suture closes too early, skull growth can be restricted in that area and redirected elsewhere. The CDC explains that when a suture closes, the baby’s head stops growing only in that part of the skull while other areas continue to grow. (CDC)
When should I ask the pediatrician about head shape?
Ask if your baby’s head shape is becoming more unusual, there is a persistent ridge, the forehead or eyes look asymmetric, the head is very long or triangular, the flat spot is not improving, the baby has a strong head-turning preference, or head growth is not following the expected curve.
When should I seek urgent medical advice?
Seek urgent medical advice if your baby is difficult to wake, has repeated vomiting, has seizure-like activity, has trouble breathing, has a persistently bulging soft spot, has poor feeding with dehydration signs, or seems seriously ill. Johns Hopkins lists a full or bulging fontanelle, poor feeding, projectile vomiting, decreased alertness, and developmental delays among possible signs of elevated intracranial pressure in craniosynostosis. (Hopkins Medicine)
Suggested External Sources for the Published Blog
Use these at the bottom of the published article as a “Sources” section:
Mayo Clinic — Craniosynostosis: Symptoms and Causes Best for: explaining skull plates, sutures, fontanelles, brain growth, and how early suture closure changes head shape. (Mayo Clinic)
American Academy of Pediatrics — Identifying the Misshapen Head: Craniosynostosis and Related DisordersBest for: normal skull anatomy, suture function, fontanelle closure, differentiating craniosynostosis from deformational head-shape changes, and referral context. (American Academy of Pediatrics)
CDC — Craniosynostosis Best for: parent-level explanation of craniosynostosis, how early suture closure affects skull growth, and why multiple fused sutures can raise pressure concerns. (CDC)
Stanford Medicine Children’s Health — Anatomy of a Newborn Baby’s SkullBest for: basic newborn skull anatomy, fontanelle location, protective membranes, and why early suture fusion changes skull growth direction. (Stanford Children's Health)
HealthyChildren.org / American Academy of Pediatrics — Your Baby’s HeadBest for: newborn molding, cone-shaped heads, soft spot reassurance, normal pulsation, and parent-friendly newborn head-shape explanations. (HealthyChildren.org)
HealthyChildren.org / American Academy of Pediatrics — Back to Sleep, Tummy to PlayBest for: safe sleep, tummy time, positional flattening prevention, and parent guidance on reducing flat spots safely. (HealthyChildren.org)
Children’s Hospital Colorado — Anterior and Posterior Fontanelle ClosuresBest for: parent-level explanation of fontanelle timing, normal soft spot feel, and when bulging or sunken fontanelles should be discussed with a doctor. (Children's Hospital Colorado)
MedlinePlus — Newborn Head Molding Best for: newborn molding during birth, flexible skull bones, sutures, fontanelles, and temporary head-shape changes after delivery. (MedlinePlus)