Growth changes in measurements of upper facial positioning

Abstract

Growth changes in the position of the midline upper face are examined for samples of Pan troglodytes, Gorilla gorilla, and modern humans. Horizontal and vertical distances between nasion and the anterior end of the cribriform plate are plotted against stage of dental development. Kendall's nonparametric correlations between facial positioning and stage of dental development are tested for significance. In African apes, the upper face becomes more projecting and positioned higher relative to the anterior cranial base. The extent of this horizontal and vertical separation reflects primarily facial size. In modern humans, the upper face becomes more projecting but is relatively stable in its vertical position. Comparison of Pan and modern human crania in the youngest dental age category indicates that the upper face of modern humans is positioned lower early in postnatal life. The position of the upper face (glabella) relative to the anterior and posterior cranial base is presented for several fossil hominid crania. The fossil crania are similar to Pan and modern humans in facial projection relative to the anterior cranial base. However, glabella is positioned low in the fossil crania. Total facial projection (relative to hormion) for Sts 5 is similar to the mean for Gorilla. Fossil Homo and robust australopithecine crania display very projecting upper faces. We suggest that the upper face of Homo is projecting due to the length of the anterior cranial fossa, while robust australopithecines possess a thick frontal bone.

A review of the literature on the aging adult skull and face: Implications for forensic science research and applications

“…From an evolutionary perspective, there are comparative studies on craniofacial variation and growth changes among humans and other apes, e.g. [29][30], and secular changes in modern humans [31]. There is also some population-based information on craniofacial age changes in non-white populations, such as growth in African Americans [32], aging in black Africans [33], and a comparison of skin aging between Chinese and European populations [34].…”

The primate cranial base: Ontogeny, function, and integration

“…Most importantly, the top and back of the face appear to form an integrated unit, the "facial block" which rotates during ontogeny around an axis through the intersection of the anterior and middle cranial fossae at the front of the greater wings of the sphenoid (McCarthy and Lieberman, 2001). This facial block is characteristic of anthropoids but not strepsirhines, and manifests itself through correlations between cranial base angle and upper facial orientation in primates (Weidenriech, 1941;Moss and Young, 1960;Biegert, 1963;Shea, 1985aShea, , 1986Shea, , 1988Ravosa, 1988Ravosa, , 1991aRoss and Ravosa, 1993;Ross, 1995a,b;May and Sheffer, 1999;Lieberman, 2000;Ravosa et al, 2000aRavosa et al, , 2000b. In particular, as the anterior cranial base flexes relative to the posterior cranial base, the PM plane also must flex relative to the posterior cranial base, rotating the posterior and upper portions of the face underneath the anterior cranial fossa (klinorhynchy).…”

“…More recently, Lieberman and McCarthy (1999) measured external cranial base flexion in a longitudinal sample of humans using two lines, one extending from basion to sphenobasion, and the second from sphenobasion to hormion. May and Sheffer (1999) took essentially the same measurement on cross-sectional samples of humans, chimpanzees, gorillas, and several fossil hominins. These studies all agree that flexion of the internal cranial Fig.…”

“…In particular, Lieberman (1995Lieberman ( , 1998Lieberman ( , 2000 has argued that variation in facial projection accounts for many of the major differences in overall craniofacial form between H. sapiens and other closely-related "archaic" Homo taxa, including the Neanderthals. Whereas all nonextant hominins have projecting faces, "anatomically modern" H. sapiens is uniquely characterized by a retracted facial profile in which the majority of the face lies beneath the braincase (Weidenreich, 1941;Moss and Young, 1960;Vinyard, 1994;Lieberman, 1995Lieberman, , 1998Vinyard and Smith, 1997;May and Sheffer, 1999;Ravosa et al, 2000b). As a consequence, H. sapiens also has a more vertical frontal profile, less projecting browridges, a rounder overall cranial shape, and a relatively shorter oropharyngeal space between the back of the hard palate and the foramen magnum-virtually all of the supposed autapomorphies of "anatomically modern" H. sapiens.…”

Three‐Dimensional Geometric Morphometric Analysis of the Nasopharyngeal Boundaries and Its Functional Integration with the Face and External Basicranium Among Extant Hominoids

“…The latter has been examined for its potential relationship with brain size where greater encephalization has been related to downward flexion of the clivus (e.g., Biegert, 1963;Gould, 1977;Ross and Ravosa, 1993;Ross and Henneberg, 1995;Strait, 1999; but see Jeffery and Spoor, 2004). Increased internal basicranial flexion has also been related to neurocranial vault "rounding" (Huxley, 1867;Lieberman et al, 2000), orthognathy (e.g., Virchow, 1857;Ranke, 1892;Ashton, 1957;Enlow, 1975;May and Sheffer, 1999), and increased facial kyphosis (e.g., Ross and Ravosa, 1993). Few researchers have considered the potential relationships between external and internal basicranial flexion.…”