Craniosynostosis: Symptoms, Causes, Diagnosis, and Treatment Explained
Updated: 55 minutes ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: September 2026
TL;DR: Craniosynostosis is a condition present at birth in which one or more of the joints (sutures) between the bones of a baby's skull close too early, before the brain is fully formed. Because the brain keeps growing, it pushes outward through the still-open sutures, shaping the head atypically: long and narrow (sagittal, the most common type), flat and wide (coronal), triangular-forehead (metopic), or flat on one side (lambdoid, very rare). Symptoms are usually visible at birth and include an atypical skull shape, a raised hard ridge along the closed suture, and changes in facial or ear balance. The most common form is nonsyndromic, with an unknown cause thought to mix genetic and environmental factors; a syndromic form is tied to gene changes such as Apert, Pfeiffer, and Crouzon syndromes. Untreated intracranial pressure can cause developmental delays, learning problems, blindness, seizures, and headaches. Treatment for most babies is surgery, either endoscopic (up to about 6 months) or open (generally older), sometimes with springs or post-surgery helmet therapy [1] [2].
Quick Answer: Craniosynostosis happens when one or more sutures, the flexible joints between the bony plates of a baby's skull, fuse too early, before the brain is fully formed. The brain keeps growing and reshapes the head through the sutures that remain open, producing a shape that's not typical. Signs show up at birth or in the first months: an unusual head shape, a raised hard ridge along the suture, and shifts in facial or ear balance. It can run alone (nonsyndromic, most common) or with genetic syndromes like Apert, Pfeiffer, or Crouzon. Diagnosis is made by specialists through exam, CT/MRI imaging, and sometimes genetic testing. For most babies, surgery is the main treatment, endoscopic for babies up to about 6 months and open for older babies, followed by helmet therapy in some cases. After surgery, most children develop as expected with good cosmetic results [1] [2].
What Is Craniosynostosis?
Craniosynostosis (kray-nee-o-sin-os-TOE-sis) is a condition present at birth. It causes one or more of the joints between the bones of a baby's skull to close too early, before the brain is fully formed [1].
To understand it, it helps to know how a baby's head is built. The joints are called cranial sutures, made of flexible, fibrous tissue, and they hold the bones of the skull together. The sutures meet at the fontanels, the soft spots on a baby's head. The largest fontanel, called the anterior fontanel, is at the front. These sutures stay flexible during infancy, allowing the skull to grow as the brain grows [1].
Craniosynostosis usually involves early closing of one cranial suture but can involve more than one. Brain growth continues even when one or more sutures close too early. Open sutures on other sides of the head allow brain growth in those directions, and this causes the head to have a shape that's not typical [1].
"The sutures allow a baby's skull to get bigger as the brain grows. The sutures usually close when the brain is done growing." [1]
What Are the Symptoms of Craniosynostosis?
Symptoms of craniosynostosis usually can be seen at birth. They become easier to see during the first few months of a baby's life. Symptoms and their severity depend on how many sutures are closed and when the closing occurs during brain development [1].
The symptoms can include an atypically shaped skull, changes in the balance of facial features and ears, and a raised hard ridge along the closed suture.
Symptom | What to look for |
Atypical skull shape | Shape depends on which sutures are closed; the brain keeps growing on the sides with open sutures |
Facial and ear imbalance | For example, one eye may be higher than the other |
Raised, hard ridge | A firm ridge runs along the closed cranial suture |
How does the head shape change by suture type?
The term given to each type of craniosynostosis depends on which sutures are affected. On the top of the head toward the front, some sutures meet at the large soft spot called the anterior fontanel, the soft spot felt just behind a baby's forehead. The next largest fontanel, called the posterior fontanel, is at the back of the head where the other sutures meet. The flexible, fibrous sutures connect the bony plates of the skull [1].
Type | Where the suture runs | What happens when it closes too early |
Sagittal | From front to back at the top of the skull, between the front and back fontanels | Forces the head to grow long and narrow; the most common type of craniosynostosis |
Coronal (one side) | From each ear to the top of the skull, meeting at the front fontanel | Forehead flattens on that side and bulges on the other; the nose turns and the eye socket rises on the affected side |
Coronal (both sides) | Same coronal path on both sides | The head looks short and wide, often with the forehead tilted forward |
Metopic | Up from the top of the bridge of the nose, through the middle of the forehead, to the front fontanel | The forehead takes on a triangular shape and the back part of the head widens |
Lambdoid | Down the back of the head from the back fontanel | One side of the head appears flat, one ear sits higher than the other, and the top of the head tilts to one side; a very rare type |
Is a different-looking head shape always craniosynostosis?
No. A head shape that's not typical doesn't always mean that a baby has craniosynostosis. If the back of a baby's head appears flattened, it could be the result of spending too much time lying on the back. This can be treated with regular position changes. If the head is very flat on one side, helmet therapy can help reshape the head to a more balanced look [1].
When should you see a doctor?
Your pediatrician or other healthcare professional monitors your child's head growth at well-child visits. Talk with your healthcare professional if you have concerns about your baby's head growth or shape [1].
What Causes Craniosynostosis?
Often the cause of craniosynostosis is not known. But sometimes it's related to genetic conditions [1].
There are two broad categories, defined by whether the condition appears alone or as part of a genetic syndrome.
Category | Cause | Notes |
Nonsyndromic craniosynostosis | Not known; thought to be a mix of genetic and environmental factors | The most common type |
Syndromic craniosynostosis | Caused by certain gene changes that cause genetic syndromes | Examples include Apert syndrome, Pfeiffer syndrome and Crouzon syndrome; these syndromes can affect skull development and usually also include other physical changes and health conditions |
What Are the Risk Factors and Complications?
Genetic syndromes that affect a baby's skull development, such as Apert syndrome, Pfeiffer syndrome and Crouzon syndrome, are risk factors for craniosynostosis [1].
If not treated, craniosynostosis may cause lasting changes in the shape of the head and face, and a feeling of not being worthy and of wanting to stay away from others [1].
The risk of higher pressure inside the skull, called intracranial pressure, from craniosynostosis is small if the suture and head shape are treated with surgery. Babies who have craniosynostosis caused by a genetic syndrome may develop higher pressure inside the skull if treatment doesn't make the skull larger to make room for their growing brains [1].
If not treated, higher pressure inside the skull can cause the following [1]:
Complication of untreated intracranial pressure | Description |
Developmental delays | Milestones are reached later than expected |
Problems with thinking, memory and learning | Cognitive functions are affected |
Blindness | Vision loss from pressure on the optic nerves |
Abnormal electrical activity in the brain | |
Headaches | Persistent pain from pressure inside the skull |
How Is Craniosynostosis Diagnosed?
Craniosynostosis is usually diagnosed by specialists, such as pediatric neurosurgeons or specialists in plastic and reconstructive surgery. Diagnosis may include [2]:
Diagnostic step | How it works |
Physical exam | The healthcare professional feels the baby's head for suture ridges and looks for changes in facial features and head shape |
Imaging studies | A CT scan and MRI of the baby's skull can show whether any sutures have fused. Cranial ultrasound imaging may be used. Sutures can't be seen after they've closed, so not seeing sutures means that they're closed. Imaging studies also may show a ridging of the suture line. Results of imaging, a laser scan and photographs may be used to make precise measurements of the skull shape and to plan surgery |
Genetic testing | If your healthcare professional suspects craniosynostosis is part of a genetic syndrome, genetic testing may help identify the syndrome |
Rarely, craniosynostosis may be suspected or diagnosed before birth [2].
How Is Craniosynostosis Treated?
Your child's care team may include a variety of specialists who are experts in managing craniosynostosis. At a center with expertise in diagnosing and treating the condition, these specialists work together in one place [2].
Mild craniosynostosis may not need treatment with surgery. For most babies, surgery is the main treatment. The type of surgery and when it's done depends on the type of craniosynostosis and whether it's part of a genetic syndrome. Sometimes more than one surgery is needed [2].
The purpose of treatment is to reshape the head, lessen or prevent pressure on the brain, and create room for the brain to grow properly [2].
How is the surgery planned?
Imaging studies help surgeons create a surgical plan. Virtual surgical planning uses high-definition 3D CT scans and MRI scans of the baby's skull to create a computer-simulated surgical plan specific to your baby's needs. Based on that virtual plan, customized models and templates are made to guide the procedure [2].
What surgical options are available?
A team that includes a specialist in surgery of the head and face (a craniofacial surgeon) and a specialist in brain surgery (a neurosurgeon) usually performs the surgery. Surgery can be done with endoscopic or open surgery. The exact surgery and when it's done depend on which and how many sutures have closed. Both types of procedures generally have very good cosmetic results with low risk of complications [2].
Feature | Endoscopic surgery | Open surgery |
Best for | Babies up to age 6 months; better done as soon as possible | Generally, babies older than 6 months |
How it's done | A lighted tube and camera (endoscope) is inserted through small scalp incisions; the surgeon removes the closed suture to let the skull expand with brain growth | The surgeon makes a cut in the scalp and cranial bones, then reshapes the skull to allow more room for brain growth |
Fixation | Not applicable | Skull position held with plates and screws that dissolve on their own over time |
Incisions | Smaller | Larger |
Hospital stay | Typically one night | Typically 3 to 4 days |
Blood transfusion | Usually not needed | Usually needed |
Number of surgeries | Part of a two-step path (surgery plus helmet therapy) | Generally one-time; babies with complex craniosynostosis often need more open surgeries |
To help widen the space between the skull bones once a closed suture has been removed, springs may be placed in the gap. This is called spring-mediated cranioplasty, and placement can be done as part of open surgery or endoscopic surgery. Another surgery is needed to remove the springs [2].
Is helmet therapy needed after surgery?
After minimally invasive surgery, the baby has regular office visits to fit a series of helmets to help shape the skull. The surgeon talks with you about how long helmet therapy is needed based on how quickly the head shape responds to treatment. Usually a baby wears a helmet 23 hours of each day for about a year. If open surgery is done, usually no helmet is needed afterward [2].
How Can Parents Cope and Prepare?
When you learn that your baby has craniosynostosis, you may have a range of emotions, and you may not know what to expect. Information and support can help [2].
Finding a team of trusted professionals matters. You'll likely need to make important decisions about your baby's care. Medical centers with craniofacial specialty teams can offer information about the condition, coordinate your baby's care among specialists, help you look at treatment options, and provide treatment [2].
Seeking out other families helps, too. Talking with people dealing with the same kinds of challenges can provide information and emotional support. Ask your healthcare professional about support groups in your community. If an in-person group isn't for you, your healthcare professional may put you in touch with a family who has a child with craniosynostosis, or you may find group or individual support online [2].
Most importantly, stay positive: most children develop as expected and have good cosmetic results after surgery. Early diagnosis and treatment are key. When needed, early intervention services offer help with developmental delays or intellectual disabilities [2].
Preparing for your appointment
Sometimes a pediatrician may suspect craniosynostosis at a routine well-baby visit, or you may make an appointment because of concerns about your baby's head growth. Your healthcare professional can refer you to a specialist. If possible, take a family member or friend, who can help remember information and provide emotional support [2].
Before the appointment, list any symptoms you've noticed, such as raised ridges or changes in the shape of your baby's face or head, plus questions to ask. Suggested questions include what the most likely cause is, what tests the baby needs, what treatments are available and suggested, the risks of surgery, who will perform it, what happens if surgery isn't done right away, whether the skull shape will affect the brain, and the chances that future children will have the same condition [2].
Your healthcare professional is likely to ask when you first noticed the changes in head shape, how much time the baby spends lying on the back, the baby's sleep position, whether development matches other children of the same age, whether there were pregnancy complications, and whether there's a family history of craniosynostosis or genetic conditions such as Apert, Pfeiffer or Crouzon syndrome [2].
Conclusion and Next Steps
Craniosynostosis is a mechanical problem with a well-defined solution. When a skull suture fuses before the brain is done growing, the growing brain simply pushes the head into an atypical shape: long and narrow, short and wide, triangular, or flat on one side depending on which suture closed. Because the shape itself points to the affected suture, a careful exam plus imaging tells specialists exactly what they're working with, and virtual surgical planning now lets teams design a procedure around your baby's own skull.
The outlook, when addressed early, is reassuring: most children develop as expected and finish with a more typical head and face shape after surgery. The complications worth preventing (developmental delays, learning problems, vision loss, seizures, headaches) stem from pressure inside the skull that early treatment removes. And not every unusual head shape is craniosynostosis; many cases are positional and improve with simple changes in position or helmet therapy on its own.
Call to action: If you've noticed a raised hard ridge on your baby's head, a head shape that looks unusual, or an eye or ear that sits unevenly, mention it at your next well-child visit, or call sooner if it worries you. If a diagnosis is confirmed, seek a craniofacial team that combines a craniofacial surgeon and a neurosurgeon in one center, ask about endoscopic versus open surgery for your baby's age, and connect with other craniosynostosis families for support. Write down your questions before each appointment, bring a second set of ears, and remember the key fact: early diagnosis and treatment are the difference-makers.
For education only; this article is not medical advice. Concerns about a baby's head growth or shape should be discussed with a pediatrician or a craniofacial specialist.
Frequently Asked Questions
What is craniosynostosis?
Craniosynostosis (kray-nee-o-sin-os-TOE-sis) is a condition present at birth that causes one or more of the joints between the bones of a baby's skull to close too early, before the brain is fully formed. [1]
What are cranial sutures and fontanels?
Cranial sutures are joints made of flexible, fibrous tissue that hold the bones of a baby's skull together. They meet at the fontanels, the soft spots on a baby's head. They remain flexible during infancy, allowing the skull to grow as the brain grows. The largest fontanel is the anterior fontanel, at the front; the next largest is the posterior fontanel, at the back. [1]
Why does early suture closing change the head's shape?
Brain growth continues even when one or more sutures close too early. Open sutures on other sides of the head allow brain growth in those directions, which causes the head to have a shape that's not typical. [1]
What are the symptoms of craniosynostosis?
Symptoms usually can be seen at birth and become easier to see during the first few months of life. They include a skull with a shape that's not typical, a change in the balance of facial features and ears (for example, one eye higher than the other), and a raised, hard ridge along the closed cranial suture. [1]
What is the most common type of craniosynostosis?
Sagittal craniosynostosis, in which the sagittal suture, running front to back at the top of the skull, closes too early and forces the head to grow long and narrow. [1]
What are the four types of craniosynostosis?
Sagittal (head grows long and narrow), coronal (flattened or bulging forehead, turned nose, raised eye socket on one side; both sides closing early makes the head short and wide), metopic (triangular forehead, widened back of head), and lambdoid (one side of the head flat, one ear higher, head tilts to one side; very rare). [1]
Does every unusual head shape mean craniosynostosis?
No. A head shape that's not typical doesn't always mean that a baby has craniosynostosis. A flattened back of the head could result from spending too much time lying on the back and can be treated with regular position changes. If the head is very flat on one side, helmet therapy can help. [1]
What causes craniosynostosis?
Often the cause is not known. Sometimes it's related to genetic conditions. [1]
What is the difference between syndromic and nonsyndromic craniosynostosis?
Nonsyndromic craniosynostosis is the most common type; its cause is not known but is thought to be a mix of genetic and environmental factors. Syndromic craniosynostosis is caused by certain gene changes that cause genetic syndromes, such as Apert, Pfeiffer and Crouzon syndromes, which usually also include other physical changes and health conditions. [1]
What are the risk factors?
Genetic syndromes that affect a baby's skull development, such as Apert syndrome, Pfeiffer syndrome and Crouzon syndrome, are risk factors for craniosynostosis. [1]
What happens if craniosynostosis is not treated?
It may cause lasting changes in the shape of the head and face and a feeling of not being worthy and of wanting to stay away from others. Higher pressure inside the skull can also develop in some cases. [1]
How serious is intracranial pressure with craniosynostosis?
The risk of higher intracranial pressure is small if the suture and head shape are treated with surgery. Babies with syndromic craniosynostosis may develop higher pressure if treatment doesn't make the skull larger to make room for their growing brains. [1]
What can untreated intracranial pressure cause?
Developmental delays, problems with thinking, memory and learning, blindness, seizures, and headaches. [1]
Who diagnoses craniosynostosis?
Usually specialists, such as pediatric neurosurgeons or specialists in plastic and reconstructive surgery. [2]
How is craniosynostosis diagnosed?
Through a physical exam (feeling for suture ridges, looking at facial features and head shape), imaging studies (CT scan, MRI, possibly cranial ultrasound), and, if a genetic syndrome is suspected, genetic testing. Sutures can't be seen after they've closed, so not seeing sutures means they're closed. Imaging, a laser scan and photographs may make precise skull-shape measurements used to plan surgery. Rarely, it may be suspected or diagnosed before birth. [2]
Does craniosynostosis always need surgery?
No. Mild craniosynostosis may not need treatment with surgery. For most babies, however, surgery is the main treatment. The type and timing depend on the type of craniosynostosis and whether it's part of a genetic syndrome. [2]
What is the goal of treatment?
To reshape the head, lessen or prevent pressure on the brain, and create room for the brain to grow properly. [2]
What is endoscopic surgery for craniosynostosis?
Minimally invasive surgery that may be considered for babies up to age 6 months, better done as soon as possible. A lighted tube and camera (endoscope) is inserted through small scalp incisions, and the surgeon removes the closed suture to allow the skull to expand with brain growth. Compared with open surgery, it has smaller incisions, typically involves only a one-night hospital stay, and usually does not need a blood transfusion. [2]
What is open surgery for craniosynostosis?
Generally done for babies older than 6 months. The surgeon makes a cut in the scalp and cranial bones, then reshapes the skull to allow more room for brain growth, holding the position with plates and screws that dissolve on their own over time. It typically involves a hospital stay of 3 to 4 days, usually needs a blood transfusion, and is generally a one-time procedure, though babies with complex craniosynostosis often need more open surgeries. [2]
What are the surgical results like?
Both endoscopic and open procedures generally have very good cosmetic results with low risk of complications. [2]
What is spring-mediated cranioplasty?
Springs placed in the gap to help widen the space between the skull bones once a closed suture has been removed. Placement can be part of open or endoscopic surgery, and another surgery is needed to remove the springs. [2]
What is virtual surgical planning?
Using high-definition 3D CT scans and MRI scans of the baby's skull to create a computer-simulated surgical plan specific to your baby's needs, with customized models and templates made to guide the procedure. [2]
Is helmet therapy needed after surgery?
After minimally invasive surgery, yes. Regular office visits fit a series of helmets to shape the skull; usually a baby wears a helmet 23 hours each day for about a year. If open surgery is done, usually no helmet is needed afterward. [2]
Who performs the surgery?
A team that includes a craniofacial surgeon (specialist in surgery of the head and face) and a neurosurgeon (specialist in brain surgery) usually does the surgery. [2]
Can craniosynostosis be found before birth?
Rarely, it may be suspected or diagnosed before birth. [2]
What should I do while waiting for an appointment?
Write down symptoms you've noticed (raised ridges, changes in face or head shape) and your questions, including the likely cause, needed tests, treatment options, surgical risks, who would operate, what happens if surgery is delayed, brain effects, and recurrence risk for future children. [2]
What questions will the doctor ask us?
When you first noticed changes in head shape, how much time the baby spends lying on the back, sleep position, whether development matches other children of the same age, pregnancy complications, and family history of craniosynostosis or genetic conditions such as Apert, Pfeiffer or Crouzon syndrome. [2]
How should parents cope with the diagnosis?
Find a team of trusted professionals (craniofacial specialty teams coordinate care and treatment options), seek out other families through support groups or online communities, and stay positive: most children develop as expected and have good cosmetic results after surgery. Early diagnosis and treatment are key, and early intervention services help with developmental delays or intellectual disabilities when needed. [2]
Related Reading
Sources and Further Reading
Suggested further reading:
References
Source pages dated Aug. 01, 2025. This article is for education only and is not medical advice.
Comments