Trigonocephaly

Trigonocephaly is the premature closure of the metopic suture causing the inability of the frontal bones to grow laterally, thus forming a triangular forehead with an obvious or subtle osseous ridge. The term "trigonocephaly" was coined by Welcker in 1862. The word metopic comes from the Greek word "metopon," which translates to the forehead. The premature fusion of the metopic suture, a type of craniosynostosis, produces a narrow forehead, causing the position of the eyes to be closer than usual (hypotelorism), raised or arched eyebrows, and lateral orbital retrusion with associated bilateral frontotemporal narrowing and compensatory occipital-biparietal widening. It should be distinguished from the benign metopic ridge, where hypotelorism and frontotemporal narrowing are absent and have no other clinical features. 3D computed tomography (CT) scans can be used to distinguish them.