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TEMPORALIS. 21
and from the posterior surface of the Os Malae. Outwardly, it
rises from the inner surface of the Jugum, and from the whole
inner surface of the Fascia above described. At this origin,
from the Jugum it is not to be distinguished from the Masseter,
being there, in fact, one and the same Muscle ; and indeed the
Masseter is no more than a continuation of the same origin,
under the edge of the Jugum ; and might properly enough be
reckoned the same, both as to its origin and insertion, and in
some measure in its use also.
The origin is principally fleshy ; and the Muscle passes from
it, in general, downwards, and a little forwards, converging, and
forming a thin middle tendon. After which the Muscle runs
downwards, on the inside of the Jugum, and is inserted into
the Coronoid Process of the Lower-Jaw, on both sides tendinous
and fleshy, but principally tendinous. It reaches farther down
upon the inside of the Coronoid Process, than upon the outer
side, where the insertion is continued as low as the body of the
bone.
The posterior and inferior edge of this Muscle passes over
the root of the Zygomatic Process of the Temporal Bone, as
over a pulley, which confines the action of the Muscle to that
of raising the Lower-J aw, more than if its fibres had passed in
a direct course from their origin to their insertion.
The use of the Temporal Muscle, in general, is to raise the
Lower-Jaw ; and as it passes a little forwards to its insertion, it
must bring the Condyle at the same time backwards, and so
counteract the Pterygoidseus externus of the opposite side ; and
if both Muscles act, they counteract both the Pterygoidaei, by
bringing back the whole of the Jaw. (z)
(z) [The size and development of the temporal muscle (crotaphite) is
indexed by the extent and depth of the temporal fossa, the outward or
horizontal curve described by the zygoma,togetherwith the height and the
excavations on the internal and external surfaces of the coronoid process.
As the powerful elevator of the lower jaw, it is par excellence the biting
muscle ; and it may be generally stated that its dimensions and force
will be found closely related to the development of the piercing and
cutting teeth, especially the canines. In those of the inferior Mammalia