The “Metopic Ridge”

The metopic suture is the only suture which normally closes during infancy. Upon closure, a palpable and visible ridge often forms which can be confused with metopic craniosynostosis. Benign Metopic ridging may be treated nonsurgically while metopic craniosynostosis is treated surgically. Differentiating between the two is important; however, the jury is still out about where a clear diagnostic threshold lies. Physical examination and CT scan characteristics may help to differentiate between physiological closure of the metopic suture with ridging and Metopic Craniosynostosis.

Below is an example of a benign Metopic Ridge:

smiling baby

Metopic Synostosis typically presents with the child having an unmistakable triangular forehead, narrow forehead, biparietal widening, and hypotelorism. The large majority of children with true Metopic synostosis will present prior to six months of age.

A benign metopic ridge does not require surgical treatment. It is very important that a qualified surgeon can distinguish between the two. Accurate diagnosis is very important given the fact that surgical interventions present a significant risk to the patient. In contrast to other single-suture craniosynostoses, making the diagnosis of Metopic Craniosynostosis can be challenging for the clinician for a number of reasons. First, the metopic suture is the only suture in which closure can occur as early as 2 months of age. Identification of a closed metopic suture on a CT scan in a 3-month-old therefore does not necessarily indicate premature closure; other factors must be taken into consideration. Second, closure of the metopic suture is often associated with a palpable midline ridge over the forehead.

This ridging can draw the parents’ and practitioner’s attention to the forehead and is often confused with the ridging associated with premature closure. Third, there is no gold standard for the clinical diagnosis of Metopic Synostosis. Typically, the diagnosis is made by physical examination focusing on the classic characteristics of forehead narrowing, biparietal widening, and pseudohypotelorism.

This “gray zone” merits closer scrutiny.

This is a topic that is still developing and ultimately will come down to risk vs benefit.

For more questions regarding this topic contact us!