| CHILDREN [62 mandibles, completion of milk dentition to eruption of second permanent molar] | ||||||||
|---|---|---|---|---|---|---|---|---|
| None or indistinguishable | Slight to moderate | Medium | Pronounced | |||||
| Specimens | 47 | [169]10 | [170]5 | |||||
| Per cent | 75.8 | 16.1 | 8.1 | |||||
| ADULTS [Both sexes. 710 mandibles] | ||||||||
| Specimens | 215 | 356 | 114 | 25 | ||||
| Per cent | 30.3 | 50.1 | 16.1 | 3.5 | ||||
| ADULTS [Sexes separately. M. 350; F. 360 mandibles] | ||||||||
| Males | Females | Males | Females | Males | Females | Males | Females | |
| Specimens | 71 | 144 | 193 | 163 | 67 | 47 | 19 | 6 |
| Per cent | 20.3 | 40.0 | 55.1 | 45.3 | 19.1 | 13.1 | 5.4 | 1.7 |
The significance of these hyperostoses is not yet quite clear. Danielli, who in 1884 reported them[171] in the Ostiaks, Lapps, a Kirghiz, a Peruvian Indian, and four white skulls, offered no explanation. For Søren Hansen,[172] who first suggested the resemblance of these formations to the torus palatinus, "the significance of this feature, which also occurs in other Arctic races not directly related to the Eskimos, is not clear." R. Virchow,[173] who reports "wulstigen und knolligen Hyperostosen" on both the upper and lower jaws of a Vancouver Island Indian, restricts himself to a brief mention of the condition with a suggestion as to its causation (see later). Welcker[174] found them in the skulls of a German (Schiller?), Lett, and a Chinese, but has nothing to say as to their meaning. Duckworth and Pain[175] report the "thickening" in 10 out of 32 Eskimo jaws, but do not discuss the causation; and the same applies to Oetteking,[176] who reported on a series of Eskimo from Labrador. In 1909 Gorjanovič-Kramberger[177] somewhat indirectly notes the condition, without a true appreciation of its meaning.
In 1910 I had the opportunity to report on the mandibular hyperostoses in a rare collection of crania and lower jaws of the central and Smith Sound Eskimo.[178] Of 25 lower jaws of adults and 5 of children, 18, or 72 per cent, of the former and 2 of the latter showed distinct to marked lingual hyperostoses, while in the remaining cases the feature was either doubtful (absorption of the alveolar process) or absent. Two of the five children showed the peculiarity in a well-marked degree. A critical consideration of the condition leads me to the conclusion that it is not pathological, and my remarks were worded (p. [211]) as follows: "A marked and general feature is a pronounced bony reinforcement of the alveolar arch extending above the mylohyoid line from the canines or first bicuspids to or near the last molars. This physiological hyperostosis presents more or less irregular surface and is undoubtedly of functional origin, the result of extraordinary pressure along the line of teeth most concerned in chewing; yet its occurrence in infant skulls indicates that at least to some extent the feature is already hereditary in these Eskimo."
In 1912, Kajava[179] reported lingual hyperostotic thickenings on the lower jaws of 68 adult Lapps, and found the condition in frequent association with pronounced wear of the teeth. In 1915, finally, Fürst and C.C. Hansen, in their great volume on "Crania Groenlandica," approach this question much more thoroughly. They, as also Kajava, did not know of the writer's report of 1910. They found the "torus" (p. [181]), "also in the mandibles of some various Siberian races in a not insignificant percentage * * * and also not infrequently among European races, especially in the Laplanders (30 to 35 per cent)." They also report the presence of the condition "in a Chinaman," and saw indications of a good development of it in 17 per cent of 164 middle ages to prehistoric, and in 12 per cent of later Scandinavian lower jaws. Their interesting comments on its possible causation, though at one point seemingly not harmonizing, are as follows (p. [180]): "The possibility is not precluded that we have here a formation which, even though it has at first arisen and been acquired through mechanical causes, has in the end become a racial character, albeit a variable one." And page [181]: "There seems to be no doubt whatever that it is a formation connected with Arctic races or Arctic conditions of life; and, accordingly, it can not safely be assumed to be a racial character, however difficult it is to regard it as a formation only acquired individually."
BUREAU OF AMERICAN ETHNOLOGY FORTY-SIXTH ANNUAL REPORT PLATE 61
Western Eskimo and Aleut (middle) Lower Jaws, Showing Lingual Hyperostoses. (U.S.N.M.)
With both the previously published and the present data, I believe the subject of these bony formations may now be approached with some hope of definite conclusions.
These hyperostoses give no indication of being pathological. They are formed largely, if not entirely, by compact bone tissues of evidently normal construction. They never show a trace of attending inflammation or of ulceration or of breaking down. They resemble occasionally the osteomae of the vault of the skull, and more distantly the osteomae of the auditory meatus, but in those cases where the bony swelling is uniform and in many others they show to be of quite a different category. (Pl. 61.)