The brain growth pattern in humans is distinctive among primates. In the past decades several hypotheses have been proposed to analyze cranial ontogenetic changes (i.e shape and size variations) in humans (e.g. Moss and Young, 1960; Lieberman et al., 2002; Bruner, 2004; Neubauer et al., 2009). The recent study conducted by García Gil et al. (2015) presents a preliminary approach to the histological variations of the vault bones in three individuals of different ages (child, adolescent and young adult). According to their results, it is possible to identify three different histological phases of cranial growth. In the child, vault bones are primarily composed of avascular lamellar bone (widely vascularized). In contrast, the adolescent bones show a larger extension of mineralized regions (highly remodeled areas) and low levels of vascularization, with a much reduced diploe. In the adult, the vault bone is highly vascularized and the diploe is largely expanded. The authors suggest that the sealing of the cranial bone surfaces helps to minimize the bone porosity while increases bone expansion (during childhood) and thickness (during youth). This “sealing process” could play a main role controlling head thermoregulation until the brain finishes its maturation. When confirmed on larger samples, these results can introduce new perspectives in functional craniology.
Gizéh Rangel de Lázaro