The effects of sectioning angle on measurements of enamel prism size and spacing

Comparative studies of prism size and spacing employ variables that are based on idealized, two-dimensional models. Results of modelling experiments illustrate that three-dimensional prism orientation can have a significant impact on two-dimensional measurements. In comparing prism size and spacing variables, it is essential to maintain control over the angle at which prisms are sectioned in order to compare real differences between taxa rather than preparation artefact. The further sectioning angles are from orthogonal, the greater the possibility for misrepresenting true prism size and spacing. While the survey of prism compression/extension (k) values reported here, as well as those described in previous studies, indicate that prism sectioning angles are only rarely extreme enough to render other values of prism and ameloblast size and spacing useless, the potential influence of sectioning obliquity on variation cannot be dismissed.