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Coronal suture

The coronal suture is a major fibrous joint (suture) of the skull that separates the frontal bone anteriorly from the paired parietal bones posteriorly. It runs transversely across the calvarium and is a key anatomical landmark for skull growth, cranial development, neurosurgical orientation, and imaging interpretation.

The coronal suture plays an important role during childhood skull expansion and gradually undergoes physiological fusion with age.

Synonyms

  • Frontoparietal suture

  • Coronal cranial suture

Location

  • Extends transversely across the skull vault

  • Separates the frontal bone from the parietal bones

  • Runs from one pterion region to the opposite pterion

  • Located anterior to the vertex

  • Posterior to the frontal sinus region

  • Superficial to the frontal and parietal lobes

Anatomical components

  • Frontal bone (anterior component)

  • Right and left parietal bones (posterior components)

  • Interdigitating fibrous tissue forming a serrated suture line

  • Underlying dura mater firmly adherent at the suture margins

Relations

Anteriorly:

  • Frontal bone

  • Frontal lobe cortex

Posteriorly:

  • Parietal bones

  • Parietal lobe cortex

Superiorly:

  • Scalp layers

  • Galea aponeurotica

Inferiorly:

  • Dura mater

  • Subarachnoid space and cerebral cortex

Laterally:

  • Pterion on each side

  • Temporal squama inferior-laterally

Structures related to the coronal suture

  • Underlying frontal and parietal cerebral cortices

  • Dural attachments along the suture line

  • Superficial scalp vessels crossing the suture

Function

  • Cranial growth accommodation: Allows expansion of the skull during brain growth

  • Structural stability: Maintains firm articulation between frontal and parietal bones

  • Anatomical landmark: Used in cranial measurements, neurosurgery, and imaging orientation

  • Force distribution: Helps dissipate mechanical forces across the skull vault

X-ray appearance

Skull radiographs (AP / lateral views):

  • Coronal suture: Serrated radiolucent line extending laterally across the skull

  • Margins: Interdigitating, irregular borders

  • Symmetry: Normally symmetric on both sides

  • Age-related change: May appear less distinct with progressive fusion

CT appearance

Non-contrast CT:

  • Suture line: Hypodense linear gap between frontal and parietal bones

  • Edges: Well-defined cortical margins

  • Diploë: Continuous across adjacent bones

Post-contrast CT:

  • Calvarial bones: No enhancement

  • Adjacent dura: May show mild physiologic enhancement

3D CT VRT appearance

Volume-rendered technique (VRT):

  • Suture course: Clearly visualized as a transverse seam across the skull vault

  • Bone contours: Smooth articulation between frontal and parietal bones

  • Fusion status: Degree of suture visibility varies with age

  • Clinical utility: Excellent for assessing skull shape, symmetry, and suture morphology

MRI appearance

T1-weighted images:

  • Suture: Low-signal linear gap between calvarial bones

  • Diploic marrow: Intermediate to high signal

  • Scalp fat: High signal

T2-weighted images:

  • Suture region: Low signal corresponding to fibrous tissue and cortical bone

  • Adjacent cortex: Normal frontal and parietal lobe signal

CT VRT 3D image

Coronal suture