Page 120 - My FlipBook

104 HUNTER ON THE TEETH.

The Teeth in the Upper-Jaw are placed farther back in the
circle than the corresponding Teeth of the Lower ; this is owing
to the two first Incisores above being broader than the corre-
sponding Incisores below. All the Teeth have only one fang,
except the Grinders, each of which has two in the Lower-Jaw,
and three in the Upper.*
The fangs bear a proportion to the bodies of the Teeth;
and the reason is evident, for otherwise they would have been
easily broken, or pushed out of their sockets. The force com-
monly applied to them is oblique, not perpendicular ; and they
are not so firmly fixed in the Upper-Jaw, that is, the Alveolar
Process in that is not so strong as in the Under-Jaw : it is per-
haps on this account, that the Grinders in that Jaw have three
fangs.
This particular structure in the Alveolar Process of the Upper-
Jaw, is perhaps to give more room for the Antrum Hiyhmori-
anum; on this supposition the fangs must be made accordingly,
i.e. so that they shall not be pushed into that cavity ; now, by
their diverging, they inclose as it were the bottom of the
Antrum, and do not push against its middle, which is the
weakest part ; and the points of three diverging fangs will make
a greater resistance (or not be so easily pushed in) than if they
were placed parallel. If there had been only two, as in the
Lower-Jaw, they must have been placed opposite to the thinnest
part of the Antrum ; and three points placed in any direction
but a diverging one, would have had here much the same effect
as two ; and as the force applied is endeavouring to depress the
Tooth, and push it inwards, the innermost fang diverges most
and is supported by the inner wall of the Antrum. That all

* Those Anatomists who allow the Teeth to have more fangs, have
been led into a mistake, I suppose, by often observing two canals in one
fang ; and thence concluded, that such a fang was originally two, and
that these were now growing together, (q)

(q) [This observation of Hunter's is itself a mistake. The fang of the
upper premolar really consists of two connate fangs.]