Metopic suture

The metopic suture (also known as the frontal, interfrontal, or median frontal suture) is a type of calvarial suture. It is often associated with frontal sinus agenesis or hypoplasia ⁷. 

Gross anatomy

This suture runs through the midline across the frontal bone from the nasion to the bregma, although it may often be incomplete. It may fuse as early as 3 months of age and should fuse in nearly all patients by around 9 months of age ^1-4. 

A premature fusion of the suture is termed metopic synostosis (type of craniosynostosis) with can then result in trigonocephaly. 

Variant anatomy

The metopic suture is usually obliterated by about 7 years of age, but in rare cases it can persist ⁶ as an anatomical variant of little clinical significance but that it can be mistaken for frontal bone fracture.

Differential diagnosis

• frontal bone fracture
  • metopic sutures have a characteristic midline position and demonstrate sutural interdigitations ⁴