Artificial cranial deformation and the increased complexity of the lambdoid suture

Abstract

Studies examining an association between artificial cranial deformation and the presence of wormian bones in the lambdoid suture have been inconclusive. Cranial deformation, however, does not seem to have a direct effect of increasing the sutural complexity of the pars lambdica of the lambdoid suture and also increasing the mean number of lambdoidal wormian bones, given their presence.

Test of the relationship between sutural ossicles and cultural cranial deformation: Results from Hawikuh, New Mexico

“…Although two other reports (Gottlieb, 1978;O'Loughlin, 2004) found an association between posterior, tabular deformation and an increase in the number of ossicles at the lambdoid and sagittal sutures, these results are less persuasive because of the methodological issues discussed previously, including the lack of statistical testing in Gottlieb's sample. El-Najjar and Dawson (1977) did find an increased number of ossicles on the side that was more severely affected in asymmetrically deformed crania, and this intraindividual comparison is the strongest evidence that deformation from cradleboarding correlates with differences in the expression of lambdoid ossicles.…”

“…The effects of cultural cranial deformation on cranial nonmetric trait expression have been investigated in a number of studies (Ossenberg, 1970;Passarello and Vecchi, 1974;Konigsberg et al, 1993;Del Papa and Perez, 2007). Sutural ossicles or wormian bones-defined as isolated islands of bone located within the cranial sutureshave been included in these studies as well as being the primary focus in several works exploring the relationship between deformation and cranial morphology (ElNajjar and Dawson, 1977;Gottlieb, 1978;Antón et al, 1992;White, 1996;O'Loughlin, 2004). Of all the nonmetric cranial traits, the potential for epigenetic influences on ossicle development is particularly promising because of their location at the suture margins where active growth continues postnatally (Mao, 2002).…”

“…Furthermore, the reports of increases in the prevalence or number of ossicles for deformed crania are problematic. Gottlieb's (1978) work is limited by the small available sample of only 12 deformed and 17 undeformed crania, and no testing for statistical significance. In O'Loughlin's (2004) more recent study encompassing several forms of deformation, the deformed sample includes a large percentage of South American crania and the undeformed sample has none.…”

Cranial deformation and nonmetric trait variation

“…However, these two early studies did not compare nonmetric trait frequencies between deformed crania within individual populations, and consequently it was impossible to tell whether trait frequency differences were due to deformation or to between-population variation. In more recent studies, researchers have contrasted trait frequencies across deformation status (or some proxy measure) within populations (e.g., Bennett, 1965;Ossenberg, 1970;Buikstra, 1976;El-Najjar and Dawson, 1977;Gottlieb, 1978;Shipman et al, 1990). Further, Pucciarelli (1974) has shown in experimental studies of rats that deformation can increase the relative frequency of wormian bones.…”

Solubility and metastable zone width of DL‐tartaric acid in aqueous solution

“…The small sample size and the fragmentary nature of the skulls, analysed here, allow neither for comparisons to be made on the frequency of sutural bones nor investigations into the aetiological relationship between headshaping and the occurrence of supernumerary ossicles (Ossenberg, 1970; Gottlieb, 1978; Antòn et al ., 1992; Konigsberg et al ., 1993; White, 1996; O'Loughlin, 2004). It is also noted that age‐related sutural changes and obliteration can be misleading; consequently, observations on sutural complexity should be made only on adults who have not exceeded 40 years of age, as determined by patterns of cranial suture fusion (Meindl & Lovejoy, 1985), which is the case of the specimen with the shaped head examined here.…”