The purpose of this paper is to report on the relationship between the parietal foramen and complexity of the human sagittal suture. Examination of 110 Japanese human skulls (males=67, females=43) with at least one parietal foramen revealed that the sagittal suture in the area of the Obelion was the simplest portion (i.e., fewest interdigitations and shortest length) of the suture (paired ttest, P<0.0005), when compared to the outstretched suture length of three established sections: 1. Parietal foramen section (P); 2. Anterior to section P (B); and 3. Posterior to section P (L). Sutural complexity was also compared between individuals with unilateral foramen (n=48) and bilateral foramina (n=62) to see if there was a statistically significant difference. The results revealed a slight difference in section P (ANOVA Bonferroni, P<0.05), denoting that the sagittal suture at the Obelion in individuals with unilateral parietal foramen is more complex than in individuals with bilateral foramina. While no difference in sex was noted, this simplicity in part likely reflects redirected bone stresses around a circular opening resulting in reduced tensile stresses and increased compressive stresses adjacent to the parietal foramen. This phenomenon warrants additional research and has implications for bone biomechanics and development of the cranial sutures.