These hypertrophies or hyperostoses are rarely met with also in
the jaws of the Indian and other people. They are symmetric and
characteristic, though often more or less irregular. They generally
extend from the vicinity of the lateral incisors or the canines
backward, forming when more developed a marked bulge on each side
opposite the bicuspids, which gives the inner contour of the jaw when
looked at from above a peculiar elephantine appearance. They may occur
in the form of smooth, oblong, somewhat fusiform swellings, or as a
continuous more or less uneven ridge, or may be represented by from
one to four or five more or less rounded or flattened hard "buttons"
or tumorlike elevations. In development they range from slight to very
marked.
These hyperostoses have been reported by various observers (Danielli,
Søren Hansen, Rudolf Virchow, Welcker, Duckworth & Pain, Oetteking,
Hrdlička, Hawkes). They received due attention by Fürst and Hansen
in their "Crania Groenlandica" (p. 178). They have been given the
convenient, though both etiologically and morphologically inaccurate,
name of "mandibular torus"; I think mandibular hyperostoses or simply
welts would be better. Fürst and Hansen found them, taking all grades
of development, in 182, or 85 per cent, of 215 lower jaws of Greenland
Eskimo; in 28 jaws, or 13 per cent, they were pronounced, the remainder
being slight to medium. A special examination of 62 lower jaws of
children and 710 lower jaws of adult western Eskimo (with a small
number from Greenland) gives the following record: