Nancy Rifenburg, M.D.

Mary Wyers, M.D.

Children's Memorial Hospital


4 month old male sent from plastic surgeon with abnormal head shape


trigonocephaly, craniosynostosis, metopic suture, CT, 1161

Publication Date: 2006-05-09


4 month old male referred by plastic surgeon with abnormal head shape


Abnormal head shape, with a triangular or wedge shaped forehead and ridging along the metopic suture, hypotelorism.


Trigonocephaly secondary to premature fusion of the metopic suture.




Craniosynostosis are generally divided into primary and secondary forms. Primary craniosynostosis refers to premature fusion of one or more cranial sutures, thought to be a developmental anomaly of the skull base. Secondary craniosynostosis refers to premature sutural closure because of other causes such as intrauterine compression of the skull, teratogenic effects or lack of brain growth. Craniosynostosis can be seen in otherwise normal infants or as part of syndromes. Overall, approximately 15% of cases are associated with syndromes.

Of the remaining 85%, 75-80% involved only one suture ("nonsyndromic") where 20-25% are multisuture.

Of the single suture nonsyndromic types, about 60% are isolated sagittal synostosis (scaphocephaly or dolichocephaly), causing a long narrow head shape.

Our case of isolated metopic synostosis (trigonocephaly)comprises about 18%.

Isolated unilateral coronal (20%) or unilateral lambdoid (5%) synostosis causes plagiocephaly.

Patients with simple nonsyndromic craniosynostoses usually have normal development, normal intelligence and are operated on because of cosmetic reasons.

It is important to remember that some cases of single or dual suture synostosis may be genetic (especially coronal synostoses).

Three dimensional reformatted CT images of the calvarium is the definitive way to diagnose suture synostosis.

Neuroimaging is used to look for underlying brain anomalies. Infants with trigonocephaly may rarely have anterior midline anomalies such as holoprosencephaly.


  1. Pediatric Neuroimaging by A. James Barkovich Fourth Edition, 2005. pp 410-414

4 images