A note on the morphology of the metopic suture in the human skull.

The metopic suture of 24 adult skulls investigated showed recognisable varied morphological patterns. The metopic suture resembled wavy lines and was sometimes highly convoluted, especially in the superior part of the frontal bone. The mean suture length was computed as 123.1 mm (SD = 5.307) and the mean fractal dimension was 1.17 (SD = 0.076). Visual inspection of the morphological character of the metopic sutures revealed complex variation in their course between the nasion and the bregma. Comparison of the fractal dimensions indicated a two-fold increase in complexity between the anterior half of the suture terminating in the nasion (FD = 1.10) and the second half of the suture beginning in the bregma (FD = 1.21). The Mann-Whitney test confirmed the statistical significance of the differences in the fractal dimensions calculated. The variety and complexity of the interdigitations in the anterior and posterior part of the suture point to possible alterations to local strains, which occur during the growth of the braincase.