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OF THE ARTICULATION OF THE LOWER-JAW. 11

nence may, on a first view of it, appear to project considerably
below the cavity, yet a line drawn from the bottom of the cavity,
to the most depending part of the eminence, is almost hori-
zontal, and therefore nearly parallel with the line made by the
grinding surfaces of the Teeth in the Upper-Jaw: and when we
consider the Articulation farther, we shall find that these two
lines are so nearly parallel, that the Condyle moves almost
directly forwards, in passing from the cavity to the eminence ;
and the parallelism of the motion is also preserved by the shape
of an intermediate cartilage.
In this joint there is a moveable cartilage, (s) which, though
common to both Condyle and cavity, ought to be considered
rather as an appendage of the former than of the latter, being
more closely connected with it ; so as to accompany it in its
motion along the common surface of both the cavity and
eminence. This cartilage is nearly of the same dimensions with
the Condyle, which it covers; is hollowed on its inferior sur-
face, to receive the Condyle : (t) on its upper surface it is more
unequal, being moulded to the cavity and eminence of the
articulating surface of the Temporal Bone, though it is con-
siderably less, and is therefore capable of being moved with the
Condyle, from one part of that surface to another. Its texture
is ligamento-cartilagineous. This moveable cartilage is con-
nected with both the Condyle of the Jaw, and the articulating
surface of the Temporal Bone, by distinct ligaments, arising
from its edges all round, (u) That by which it is attached to the

(s) [The inter-articular fibre-cartilage. It is the only inter-articular
fihro-cartilage into which muscular fibres are inserted—viz., a portion
of the external pterygoid, which it receives along its anterior border, ami
which is instrumental in moving the fibro-cartilage in the antero-
posterior motion of the condyle. The inter-articular fibro-cartilage is
constantly found in animals which suckle their young, but not in the
inferior vertebrata.]
(t) [The inter-articular fibro-cartilage is thicker at the edges than in the
centre ; it is not unfreijuently perforated in the latter situation.]
(u) [Thin and short ligamentous fibres [memhrawx articularis,
C2