Trigonocephaly refers to the triangular appearance of the frontal skull created by premature fusion of the metopic suture (metopic craniosynostosis) 2. Trigonocephaly accounts for around 5% of all craniosynostosis cases.
The metopic suture divides the frontal bones in the midline. It begins at the nose and continues superiorly to meet the sagittal suture. The metopic suture is usually open at birth and normally fuses in the first 12 months of life. Premature fusion prevents transverse growth of the forehead which causes a triangular shaped forehead that may be associated with orbital hypotelorism (abnormal closeness of the eyes).
- 1. Dominguez R, Oh KS, Bender T et-al. Uncomplicated trigonocephaly. A radiographic affirmation of conservative therapy. Radiology. 1981;140 (3): 681-8. Radiology (abstract) [pubmed citation]
- 2. Benson ML, Oliverio PJ, Yue NC et-al. Primary craniosynostosis: imaging features. AJR Am J Roentgenol. 1996;166 (3): 697-703. AJR Am J Roentgenol (abstract) [pubmed citation]