Tooth eruption and browridge formation

Russell, Mary Doria

doi:10.1002/ajpa.1330580107

Cited by 15 publications

(21 citation statements)

References 8 publications

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“…This may alternate with periods in which previously erupting teeth are in occlusion, chewing effort is stable, and the brow surfaces are smooth. However, Russell (1982) was unable to confirm these sequences on the Papio sample reported by Oyen et al (197913).…”

Section: The Resultscontrasting

confidence: 65%

“…This also differs from the proposed association of VP with tooth eruption stages. Russell (1982) analyzes the surface texture of the frontal bones of juvenile and subadult (age estimates ranging from 3.5 to 18 years) Australian aboriginal crania exhumed in the vicinity of the Murray River. Most showed areas of variable extent (up to 51.4%) resembling the areolar surface often seen on immature macaque and baboon brow areas, and identified as primary vascular bone.…”

Section: The Resultsmentioning

confidence: 99%

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The development of the vermiculate pattern in the brow region of crania from Indian Knoll, Kentucky

Tappen

1983

American J Phys Anthropol

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A convoluted brow surface consisting of fine ridges, grooves, and depressions, first identified in ancient fossil hominids and termed the vermiculate pattern (VP), is often low in frequency and of moderate rugosity in crania of anatomically modern human populations. Burials at Indian Knoll, Kentucky, constitute an excellent series for study of the development of the VP, since cranial surfaces are usually well preserved, there are hundreds of immature and mature individuals previously assessed for age, and the VP is high in frequency and rugosity. While a surface pattern resembling a miniature VP is found on the supraorbital surface of all newborns, it is not found on any children age 2 or older. This newborn pattern is probably different in structure and origin from the adult VP. The smooth surface characteristic of children shows evidence of changing to the VP in some adolescents, but the fullest development of the VP occurs in adults. The VP continues to develop in rugosity into the fourth decade, especially in males. These observations indicate that the human VP is different in etiology from somewhat similar brow surfaces found sporadically in immature individuals of some species of nonhuman primates. Statements lumping all vermiculate bone surfaces as "fine cancellous bone" are premature. The human VP development shows no apparent relationship to phases of tooth eruption, as postulated for the appearance of areolar surfaces on brow ridges of immature non-human primates.

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Section: The Resultscontrasting

confidence: 65%

Section: The Resultsmentioning

confidence: 99%

The development of the vermiculate pattern in the brow region of crania from Indian Knoll, Kentucky

Tappen

1983

American J Phys Anthropol

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“…When modelling the supraorbital region as a beam (cf. Oyen and Russell, 1982;Range1 et al, 1985;Russell, 1982Russell, , 1985Wolpoff, 1980), this loading regime causes the dorsal interorbital and dorsal orbital regions to experience tensile strains directed perpendicular to the midsagittal plane, while the principal compressive strains are directed anteroposteriorly, parallel to the midsagittal plane ( Fig. 5B).…”

Section: Fmwmentioning

confidence: 99%

“…Many workers have suggested that enlarged browridges are an adaptive response to counter bending of the browridges in the frontal plane (Oyen and Russell, 1982;Rangel et al, 1985;Russell, 1982Russell, ,1985Wolpoff, 1980). These same workers assert that it is the dorsal interorbital region that experiences the most intense bending stress, and moreover, that the most intense bending stresses occur during incision or anterior tooth loading, rather than during mastication or posterior tooth loading (e.g., Endo, 1966).…”

Section: Fmwmentioning

confidence: 99%

Masticatory‐stress hypotheses and the supraorbital region of primates

Hylander

Picq

Johnson

1991

American J Phys Anthropol

204

279

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The purpose of this study is to test various masticatory-stress hypotheses about the evolution and function of well-developed browridges of higher primates. This was done by measuring and analyzing patterns of in vivo bone strain recorded from three-element rosette strain gages bonded to the supraorbital region and to other portions of the bony face of Macaca fascicularis and Papio anubis during mastication and incision. The magnitude and direction of the principal strains recorded support Endo's hypothesis that the supraorbital region during mastication and incision is bent in the frontal plane (Endo, 1966). Our data do not, however, support his hypothesis that the supraorbital region is bent more during incision than during mastication. The data also demonstrate that overall levels of supraorbital strain are not larger in more prognathic subjects. Most importantly, the data indicate that the supraorbital region of nonhuman catarrhines is strained very little during mastication and incision. This indicates that there is much more supraorbital bone than is necessary both to counter masticatory loads and to provide an adequate safety factor to failure for these loads. This in turn suggests that the macaque and baboon browridges can be considerably reduced in size and still maintain these required structural characteristics. Thus, our experiments provide no support whatsoever for those hypotheses that directly link browridge morphology to masticatory stress (cf. Endo, 1966; Russell, 1983, 1985). A recent review of Endo's original work indicates that this latter statement is also true for humans (Picq and Hylander, 1989). We conclude, therefore, that there is no good reason to believe that enlarged browridges in living and/or fossil primates are structural adaptations to counter intense masticatory forces. The evolution of browridge morphology in primates is best explained on the basis of factors related to the position of the brain relative to the orbits (Moss and Young, 1960). When these structures are widely separated, as in gorillas, the large intervening space must be bridged with bone. In addition, enough bone must be present within the supraorbital and bridged regions to prevent structural failure due to non-masticatory external forces associated with highly active primates (e.g., accidental traumatic forces applied to the orbits and neurocranium). This requirement results in both pronounced browridges and in much more supraorbital bone than is necessary to counter routine cyclical stress during mastication and incision. This in turn explains why bone strains recorded from the supraorbital region are extremely small relative to other portions of the primate face during mastication and incision.

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“…These authors present evidence that the appearance of this areolar, nonlamellar bone, variously identified as fine cancellous bone, woven bone, or bundle bone [Pritchard, 1972], tends to coincide with stages of active molar eruption, and thus may indicate that brow ridge formation represents a response to masticatory forces. However, Russell [1982] was unable to con firm this developmental correspondence. It is also to be noted that the areolar surface bone can be observed in other parts of the cranium of juvenile primates.…”

Section: Discussionmentioning

confidence: 99%

Microscopic Investigations of Areolar Brow Structure in Nonhuman Primates and of Vermiculate Brow Structure in Hominids

Tappen

1988

IJFP

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The microscopic structure of bone of the brow region was studied in adult human crania showing the vermiculate surface pattern, and in immature nonhuman primates with an areolar surface. Serial sections from different parts of each brow sampled regional comparability. The human brow regions are basically similar, and differ from those of the other primates. The elevations and depressions of vermiculate surfaces are lamellar bone, usually covered by layers featuring Sharpey’s fibers. In contrast, the immature nonhuman primates do not have continuous brow surface layers. Passageways to the interior are closely spaced and separated by irregular projections. These findings indicate that fossil and modern human vermiculate surfaces are not structurally equivalent to areolar brow surfaces observed in some immature nonhuman primates. Reports describing fossil hominid brow regions as composed of ‘fine cancellous bone’ are probably erroneous and give misleading interpretations of their development and function.

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Tooth eruption and browridge formation

Cited by 15 publications

References 8 publications

The development of the vermiculate pattern in the brow region of crania from Indian Knoll, Kentucky

The development of the vermiculate pattern in the brow region of crania from Indian Knoll, Kentucky

Masticatory‐stress hypotheses and the supraorbital region of primates

Microscopic Investigations of Areolar Brow Structure in Nonhuman Primates and of Vermiculate Brow Structure in Hominids

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