Metopic Synostosis or Trigonocephaly is a hot topic among families and surgical teams.

The Metopic suture is the only suture that will close during infancy. Upon closure, the Metopic suture may form a palpable ridge aka “Metopic Ridge”. To date, there is still controversy as to where the clear diagnostic threshold lies.

A “classic case” of Trigonocephaly will only appear in 14-15% of cases. A “classic case” will include, narrow/triangular shaped forehead, biparietal widening( the parietal bones are the bones forming the central side and upper back part of each side of the skull), and hypotelorism (is an abnormal decrease in distance between the eyes).

Metopic Synostosis is likely to present before the infant is six months old.


Making the tough call:

Measuring the distance between the lateral frontal bone and the lateral orbit are an important
technique used in making this clinical diagnosis.

craniosynostosis expert

The CT scan is controversial in its usefulness for diagnosis. However, a patient presenting with “normal, physiological, fused Metopic suture (with or without ridging) will typically show what is referred to as an “M” sign.


Whereas, the prematurely fused Metopic Suture will show, what is referred to as the “Omega Sign”.

When viewing a Metopic Ridge head shape from the top down, the forehead will still be rounded which will protect the superolateral orbital rim.

When viewing a child with Metopic Synostosis, the frontal bone is straight and exposes the globe, revealing the superolateral orbital rim.

It is very important that you ask questions and find a qualified specialist.

We know how difficult this can be!
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