The frontal suture is a
fibrous joint that divides the two halves of the
frontal bone of the
skull in infants and children. Typically, it completely fuses between three and nine months of age, with the two halves of the frontal bone being fused together. It is also called the metopic suture, although this term may also refer specifically to a ''persistent frontal suture''.
If the suture is not present at birth because both frontal bones have fused (
craniosynostosis
Craniosynostosis is a condition in which one or more of the fibrous sutures in a young infant's skull prematurely fuses by turning into bone (ossification), thereby changing the growth pattern of the skull. Because the skull cannot expand perpe ...
), it will cause a keel-shaped deformity of the skull called
trigonocephaly.
Its presence in a fetal skull, along with other cranial
sutures and
fontanelles, provides a malleability to the skull that can facilitate movement of the head through the
cervical canal and
vagina during delivery. The dense connective tissue found between the frontal bones is replaced with
bone tissue as the child grows older.
Persistent frontal suture
In some individuals, the suture can persist (totally or partly) into adulthood, and is referred to as a ''persistent metopic suture''. It has a prevalence of about 4% in females and about 2% in males.
The suture can either bisect the frontal bone and run from
nasion to
bregma or persist as a partial metopic suture (see image of frontal bone)
(where part of the suture survives and is connected to either bregma or nasion) or as an isolated metopic fissure. Persistent frontal sutures are of no clinical significance, although they can be mistaken for cranial fractures.
As persistent frontal sutures are visible in
radiographs, they can be useful for the forensic identification of human skeletal remains. Persistent frontal sutures should not be confused with supranasal sutures (a small zig-zag shaped suture located at and/or immediately superior to the
glabella).
Additional images
File:Frontal suture top view.png, Human baby skull seen from top. Cranial sutures are depicted. Frontal suture is highlighted in blue.
File:Slide1MIA.JPG, Human baby skull. Anterior view.
See also
*
Ossification of frontal bone
References
Further reading
*
*
* Pediatric Plastic Surgery, Mathes and Hetz. chapter 92; nonsyndromic craniostosis.
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Bones of the head and neck
Cranial sutures
Human head and neck
Joints
Joints of the head and neck
Skeletal system
Skull