Data mining for peculiarities in the configuration of neurocranium when the metopic suture persists

The persistent metopic suture is an anatomic variation related to a specific skull configuration. Data on the proportionality of the neurocranium and the occurrence of additional variations when the metopic suture persists are still insufficient. This study presents a comparison between a metopic and a non-metopic homogenous cranial series. The most distinctive quantitative and qualitative characteristics of the skull configuration when the metopic suture persists were identified using data mining techniques. A total of 175 contemporary adult male skulls were investigated. The skulls were divided in two groups: a control series (n = 100) and a metopic series (n = 75). All skulls were scanned with a hand-held laser scanner CreaformVIUscan and polygonal models were created. For 150 of the skulls, industrial µCT scanning was performed using Nikon XT H 225 and volumetric images were generated. A total of 92 attributes, both quantitative (dimensions) and qualitative (anatomical variations of the skull), were recorded from the 3D models. The major distinctive peculiarities observed in the neurocranial configuration when the metopic suture persists concerned the dimensions of the frontal bone which was considerably shorter, wider and more convex compared to the control. The metopic skulls manifested wormian bones in the sphenoidal fontanelle, around the temporal squama and along the lambdoid suture. These supernumerary bones were considerably more common in the metopic series in comparison with the control. The most reliable model resulting from the data mining summarizes a total of five classification rules entirely based on quantitative characteristics of the frontal bone.