The frontal suture is a

fibrous joint In anatomy, fibrous joints are joints connected by Fibrous connective tissue, fibrous tissue, consisting mainly of collagen. These are fixed joints where bones are united by a layer of white fibrous tissue of varying thickness. In the skull, the ...

that divides the two halves of the

frontal bone In the human skull, the frontal bone or sincipital bone is an unpaired bone which consists of two portions.'' Gray's Anatomy'' (1918) These are the vertically oriented squamous part, and the horizontally oriented orbital part, making up the bo ...

of the

skull The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent ...

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 The cervical canal is the spindle-shaped, flattened canal of the cervix which connects the vagina to the main cavity of the uterus in most mammals. Anatomy The cervical canal communicates with the uterine cavity via the internal orifice of the ...

and

vagina In mammals and other animals, the vagina (: vaginas or vaginae) is the elastic, muscular sex organ, reproductive organ of the female genital tract. In humans, it extends from the vulval vestibule to the cervix (neck of the uterus). The #Vag ...

during delivery. The dense connective tissue found between the frontal bones is replaced with

bone tissue A bone is a Stiffness, rigid Organ (biology), organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red blood cell, red and white blood cells, store minerals, provi ...

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 Radiography is an imaging technique using X-rays, gamma rays, or similar ionizing radiation and non-ionizing radiation to view the internal form of an object. Applications of radiography include medical ("diagnostic" radiography and "therapeu ...

, 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 suture In anatomy, fibrous joints are joints connected by fibrous tissue, consisting mainly of collagen. These are fixed joints where bones are united by a layer of white fibrous tissue of varying thickness. In the skull, the joints between the bones ar ...

s are depicted. Frontal suture is highlighted in blue. File:Slide1MIA.JPG, Human baby skull. Anterior view.

Persistent frontal suture

Additional images

See also

References

Further reading