Twentieth Century Research

Parsons and Box

In 1905, F. G. Parsons and C. R. Box examined the significance of internal suture closures using 82 male and female skulls of known age (Todd and Lyon 1924:329). They (Krogman 1962:78) concluded that: 1) closure rarely occurred in a healthy skull before the age of 30; 2) between 30 and 50 years of age there is a fair amount of endocranial closure in coronal and sagittal sutures; and 3) over 60, all endocranial sutures were obliterated. Parsons and Box also suggested that less serrated (simple) sutures closed before all other sutures, and that there were no differences in closure periods for the left or right side of the skull (ibid.). They proposed that the lambdoid was the last of the vault sutures to reach complete closure (Todd and Lyon 1924:355). Overall, they concluded that Dwight was justified in his assessment that cranial sutures closed later in females and that cranial sutures were not a good indicator of age (Todd and Lyon 1924:329; Krogman 1962:78).

Frédéric

In 1906, J. Frédéric examined 255 European and 119 non-European crania of known age (Todd and Lyon 1924:329). However, only 91 European and 13 non-European crania of both sexes were opened so that the internal surface could be examined (ibid.). Following Broca, Frédéric introduced his own rating scale of 0 to 4 (open, less than one half closed, half closed, more than one half closed, and totally closed) (Krogman 1962:77-78). Examining endocranial sutures, he found that the lambdoid closed after the sagittal and coronal (Todd and Lyon 1924:355). Frédéric concluded that it was not possible to determine the age of a skull by the condition of suture union closure with any accuracy greater than +/- one decade (ibid.). However, he stated that suture closure occurred later in females, thus concurring with Dwight, Parsons and Box (Krogman 1962:78).

Bolk

In 1915, Louis Bolk calculated the absolute frequency of premature obliteration in 1820 European juvenile skulls, from which he (Bolk 1915:496) proposed the following terminology for suture closure: precocious (closure before the age of seven) and premature (closure after the age of seven but before the ‘normal’ age of closure).