Trigonocephaly is a congenital condition due to premature fusion of the metopic suture (from Ancient Greek metopon 'forehead'), leading to a triangular forehead.

[1] Trigonocephaly is probably a multifactorial congenital condition, but due to limited proof of these theories this cannot safely be concluded.

[2] The first theory assumes that the origin of pathological synostosis lies within disturbed bone formation early on in the pregnancy.

Causes can either be genetic[3][4][5][6] (9p22–24, 11q23, 22q11, FGFR1 mutation),[7] metabolic[8] (TSH suppletion in hypothyroidism)[9][10] or pharmaceutical[11] (valproate in epilepsy).

[14][15] The third theory predominates disturbed brain formation of the two frontal lobes as the main issue behind synostosis.

[citation needed] Other conditions and syndromes with trigonocephaly include: Diagnosis can be characterized by typical facial and cranial deformities.

[2][19] Observatory signs of trigonocephaly are: Imaging techniques (3D-CT, Röntgenography, MRI) show: The neuropsychological development is not always affected.

[37][21][34][38][39] However, as this technique was insufficient to correct the deformities, it is not used anymore.Distraction osteogenesis is based on creating more cranial space for the brain by gradually moving the bones apart.

[2][41][42] The simple suturectomy is presently insufficient to adjust the complicated growth restrictions caused by metopic synostosis.

[2] On the other hand, the fronto-supraorbital advancement and remodelling and the 'floating forehead technique' create sufficient space for brain growth and result in a normal horizontal axis of the orbits and supraorbital bar.

[46] The minimal invasive endoscopic surgery has been gaining attention since the early '90s, however, it has technical limitations (only strip craniectomy is possible).

[27][28][20][21][22][29][30][31][32] Seemingly surgery does not influence the high incidence of neurodevelopment problems in patients with metopic synostosis.

[2] The Austrian physician Franz Joseph Gall presented the science of phrenology in the early 19th century through his work The Anatomy and Physiology of the Nervous System in General, and of the Brain in Particular.

[63] Via a photo shown on a Facebook page, the mother of a child previously diagnosed with this condition recognised the symptoms and reported them to the family involved, resulting in an immediate diagnosis that medical professionals had overlooked in all earlier consultations.