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PubMed This is a summary of 21 peer-reviewed journal articles Updated
Pediatrics

Suture Types and Head Shapes Explained

At a Glance

Craniosynostosis occurs when a baby's skull sutures fuse prematurely. To make room for the growing brain, the skull expands parallel to the fused seam. This creates specific head shapes, like a long, narrow head in sagittal synostosis or a triangular forehead in metopic synostosis.

The human skull is a marvel of engineering, designed to expand rapidly as a baby’s brain grows. When one of the sutures (the flexible joints between skull bones) closes too early, the skull can no longer expand in that direction. To make room for the growing brain, the skull is forced to grow faster in other areas [1][2].

This predictable pattern of growth is known as Virchow’s Law: the skull stops growing perpendicular to the fused seam and instead expands parallel to it [3][1]. This is why each type of craniosynostosis creates a very specific, signature head shape.

1. Sagittal Synostosis (Scaphocephaly)

This is the most common form of single-suture craniosynostosis [4][5]. The sagittal suture runs from the front to the back along the top of the head.

  • The Shape: Because the head cannot grow wider, it becomes long and narrow, like an overturned boat. This is called scaphocephaly or dolichocephaly [6][7].
  • What to Look For: You may notice “bossing” (a prominent bulge) at the forehead and the back of the head as the brain pushes growth forward and backward [8].

2. Metopic Synostosis (Trigonocephaly)

The metopic suture runs from the top of the head down the middle of the forehead toward the nose.

  • The Shape: Fusion here creates a triangular-shaped forehead, a condition called trigonocephaly [9][10].
  • What to Look For: From above, the forehead looks pointed. You may also see a prominent vertical ridge down the center of the forehead and eyes that appear closer together than usual [9][11].

3. Coronal Synostosis

The coronal sutures run from ear to ear across the top of the head. This can happen on just one side or both.

  • Unicoronal (Anterior Plagiocephaly): Only one side fuses. This causes significant facial asymmetry, including a flattened forehead on the fused side and an eye socket that may appear pulled upward—often called a Harlequin eye deformity [12][13].
  • Bicoronal (Brachycephaly): Both sides fuse. The head cannot grow forward or backward, so it becomes very wide and short, a shape known as brachycephaly [13][14]. This type has a higher association with genetic syndromes [15][16].

4. Lambdoid Synostosis

This is the rarest form of single-suture synostosis [17][18]. The lambdoid suture is located at the very back of the head.

  • The Shape: It causes the back of the head to look flat and take on a trapezoid shape from above [19][20].
  • What to Look For: Unlike common “flat head syndrome” (positional plagiocephaly), lambdoid synostosis often causes a bony “mastoid bulge” behind the ear and may pull the ear on the flat side backward and downward [21][20].

Summary of Head Shapes

Suture Fused Technical Name Resulting Head Shape
Sagittal Scaphocephaly Long and narrow (boat-shaped)
Metopic Trigonocephaly Triangular forehead
Unicoronal Anterior Plagiocephaly Asymmetrical forehead and eyes
Bicoronal Brachycephaly Short, wide, and tall
Lambdoid Posterior Synostosis Flat back with trapezoid shape

Common questions in this guide

Why does craniosynostosis cause unusual head shapes?
When a skull suture closes too early, the skull cannot expand in that direction. To make room for the growing brain, the head grows faster in other areas, creating a predictable signature head shape based on exactly which suture fused.
What is the most common type of craniosynostosis?
Sagittal synostosis is the most common single-suture form. It restricts side-to-side growth, resulting in a long, narrow head shape often referred to as a boat shape or scaphocephaly, sometimes with bulging at the forehead and back of the head.
How does metopic craniosynostosis affect a baby's forehead?
Fusion of the metopic suture restricts normal forehead expansion, creating a triangular-shaped forehead known as trigonocephaly. Parents may also notice a hard vertical ridge running down the center of the forehead and eyes that appear closer together.
Does a flat back of the head always mean my baby has lambdoid synostosis?
Lambdoid synostosis is a very rare cause of a flat back of the head and typically creates a trapezoid shape from above. Most flat spots are actually caused by positional plagiocephaly, which is much more common and doesn't involve fused bones.
When is genetic testing recommended for craniosynostosis?
Genetic testing is frequently recommended for babies with bicoronal synostosis, where both sides of the coronal suture fuse early. This specific type of fusion has a higher association with underlying genetic syndromes.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Based on my child's head shape, which specific suture is fused?
  2. 2.Is this a single-suture (isolated) synostosis, or are there multiple sutures involved?
  3. 3.If my child has unicoronal synostosis, should we be looking for the 'Harlequin eye' deformity in their imaging?
  4. 4.What are the risks of increased intracranial pressure for this specific type of synostosis as my child gets older?
  5. 5.If my child has bicoronal synostosis, do you recommend genetic testing to rule out an underlying syndrome?
  6. 6.How will this specific type of fusion affect my child's facial symmetry over time if left untreated?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (21)
  1. 1

    Multidisciplinary care of craniosynostosis.

    Buchanan EP, Xue Y, Xue AS, et al.

    Journal of multidisciplinary healthcare 2017; (10()):263-270 doi:10.2147/JMDH.S100248.

    PMID: 28740400
  2. 2

    Ethical Considerations in Surgery for Single-suture Craniosynostosis.

    Selvaggi G, Maltese G, Kölby L, et al.

    The Journal of craniofacial surgery 2023; (34(7)):1922-1926 doi:10.1097/SCS.0000000000009590.

    PMID: 37552119
  3. 3

    Telescoping With Multiple Revolution Cranial Osteotomies in Patients With Simple Craniosynostosis.

    Caycedo DJ, Betancourt NP, Cabal M, et al.

    The Journal of craniofacial surgery 2019; (30(5)):1589-1593 doi:10.1097/SCS.0000000000005346.

    PMID: 31299775
  4. 4

    Intracranial Pressure Patterns in Children with Sagittal Craniosynostosis.

    Kalmar CL, Malphrus EL, Blum JD, et al.

    Plastic and reconstructive surgery 2024; (154(1)):135e-145e doi:10.1097/PRS.0000000000010797.

    PMID: 37285193
  5. 5

    Non-syndromic craniosynostosis.

    Alperovich M, Tonello C, Mayes LC, Kahle KT

    Nature reviews. Disease primers 2025; (11(1)):24 doi:10.1038/s41572-025-00607-4.

    PMID: 40210850
  6. 6

    Surgical Treatment for Scaphocephaly Using a Modified Melbourne Technique in Mexico: An Illustrative Case and Literature Review.

    Ferrufino Mejia R, Rodríguez-Rubio HA, Arce-Lozoya MA, et al.

    Cureus 2024; (16(11)):e73089 doi:10.7759/cureus.73089.

    PMID: 39650909
  7. 7

    Degree of Sagittal Suture Fusion, Cephalic Index, and Head Shape in Nonsyndromic Sagittal Craniosynostosis.

    Villavisanis DF, Blum JD, Cho DY, et al.

    The Journal of craniofacial surgery 2022; (33(8)):2388-2393 doi:10.1097/SCS.0000000000008782.

    PMID: 35905383
  8. 8

    Standardization of Cranial Index Measurement in Sagittal Craniosynostosis.

    Al-Shaqsi SZ, Rai A, Forrest C, Phillips J

    The Journal of craniofacial surgery 2019; (30(2)):366-369 doi:10.1097/SCS.0000000000005034.

    PMID: 30531285
  9. 9

    The metopic index: an anthropometric index for the quantitative assessment of trigonocephaly from metopic synostosis.

    Wang JY, Dorafshar AH, Liu A, et al.

    Journal of neurosurgery. Pediatrics 2016; (18(3)):275-80 doi:10.3171/2016.2.PEDS15524.

    PMID: 27153376
  10. 10

    The Endocranial Bifrontal Angle: A Longitudinal Evaluation in Two Patients With Metopic Synostosis.

    Cabrejo R, Lu X, Persing J

    The Journal of craniofacial surgery 2019; (30(6)):1644-1646 doi:10.1097/SCS.0000000000005358.

    PMID: 30939543
  11. 11

    What's in a Name? Accurately Diagnosing Metopic Craniosynostosis Using a Computational Approach.

    Wood BC, Mendoza CS, Oh AK, et al.

    Plastic and reconstructive surgery 2016; (137(1)):205-213 doi:10.1097/PRS.0000000000001938.

    PMID: 26710024
  12. 12

    Discussion: Distraction Osteogenesis for Unicoronal Craniosynostosis: Rotational Flap Technique and Case Series.

    Steinbacher DM

    Plastic and reconstructive surgery 2018; (142(6)):909e-912e doi:10.1097/PRS.0000000000005072.

    PMID: 30489531
  13. 13

    Cranioorbital Morphology Caused by Coronal Ring Suture Synostosis.

    Watts GD, Antonarakis GS, Blaser SI, et al.

    Plastic and reconstructive surgery 2019; (144(6)):1403-1411 doi:10.1097/PRS.0000000000006256.

    PMID: 31764659
  14. 14

    Case Report: Three-dimensional characteristics of craniofacial morphology in facial asymmetry due to unilateral coronal synostosis.

    Fukunaga T, Shigemi S, Konno M, et al.

    Frontiers in dental medicine 2025; (6()):1622740 doi:10.3389/fdmed.2025.1622740.

    PMID: 41235092
  15. 15

    Genetic Syndromes Associated with Craniosynostosis.

    Ko JM

    Journal of Korean Neurosurgical Society 2016; (59(3)):187-91 doi:10.3340/jkns.2016.59.3.187.

    PMID: 27226847
  16. 16

    [A case report of Muenke syndrome with soft cleft palate and literature review].

    Sun J, Wang Y, Shi B, Jia Z

    Hua xi kou qiang yi xue za zhi = Huaxi kouqiang yixue zazhi = West China journal of stomatology 2025; (43(2)):275-279 doi:10.7518/hxkq.2024.2024244.

    PMID: 40132974
  17. 17

    Nonsyndromic Craniosynostosis and Deformational Head Shape Disorders.

    Morris LM

    Facial plastic surgery clinics of North America 2016; (24(4)):517-530 doi:10.1016/j.fsc.2016.06.007.

    PMID: 27712818
  18. 18

    Fusion patterns of major calvarial sutures on volume-rendered CT reconstructions.

    Wilkinson CC, Stence NV, Serrano CA, et al.

    Journal of neurosurgery. Pediatrics 2020; (25(5)):519-528 doi:10.3171/2019.11.PEDS1953.

    PMID: 32032951
  19. 19

    Isolated Frontosphenoidal Craniosynostosis: The Alder Hey Experience and a Novel Algorithm to Aid Diagnosis.

    Hennedige A, Bridle R, Richardson D, et al.

    The Journal of craniofacial surgery 2021; (32(1)):331-335 doi:10.1097/SCS.0000000000007176.

    PMID: 33055560
  20. 20

    Frontofacial Features of Unilateral Lambdoid Craniosynostosis: A Multicenter Assessment.

    Lee J, Naran S, Mazzaferro D, et al.

    Plastic and reconstructive surgery. Global open 2023; (11(5)):e5011 doi:10.1097/GOX.0000000000005011.

    PMID: 37360231
  21. 21

    Distinguishing Craniomorphometric Characteristics of Unilateral Lambdoid Craniosynostosis.

    Allam O, Park KE, Pourtaheri N, et al.

    The Journal of craniofacial surgery 2021; (32(1)):125-129 doi:10.1097/SCS.0000000000007098.

    PMID: 33156173

This page explains craniosynostosis head shapes and suture types for educational purposes. Always consult a pediatric neurosurgeon or craniofacial specialist for an accurate medical diagnosis of your baby's head shape.

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