An anatomical study on metopic suture variants in Greek adult dried skulls

Background: The metopic suture (MS), at the vertical axis between the two halves of the frontal bone appears as the result of lack of ossification. Its persistence is called metopism. The current study records the frequency of MS persistence, its morphological variants, and its coexistence with Wormian bones (WBs) in adult skulls.Material – Method: Eighty (41 male and 39 female) Greek adult dried skulls were investigated for the MS presence. For a further MS evaluation, the skulls were divided into 3 groups: 1st group (MS absence), 2nd group (complete MS) and 3rd group (incomplete MS). The incomplete MS was classified into the following morphological variants: Y, V, U, H shapes and linear and double linear types. Skulls used were also inspected for the WBs presence.Results: The MS was identified in 69 skulls (86.25%). Its absence was found in 11 skulls (13.8%) with similar frequencies in males and in females. The incomplete MS was prevalent (78.8%), while the complete one (metopism) was recorded in 7.5%. The incomplete MS dominant type was the linear (26.3%) followed by the V-type (17.5%), the double linear (15%), the H-type (8.8%), the U-type (6.3%) and the Y-type (5%). A percentage of 20% of the skulls had WBs in the lambdoid suture. A unique trigonocephaly case was identified with WBs in the lambdoid suture.Conclusion: The knowledge of MS persistence is valuable in clinical practice, as it can be erroneously considered as a frontal bone fracture in imaging studies. Neurosurgeons are obliged to be aware of this variant to provide the patient with the most appropriate and safe care. Furthermore, metopism is important in paleo-demography and forensic medicine