Page 22 - My FlipBook
P. 22
; ;
OF THE LOWER-JAW.
the Upper-Jaw, have more fangs than those that correspond
with them in the lower, and the sockets are accordingly more
irregular. The Alveolar Process of the Upper-Jaw, is a section
of a larger circle than that of the lower, especially when the
Teeth are in the sockets. This arises chiefly from the anterior
Teeth in the Upper-Jaw being broader and flatter than those in
the Lower. The posterior part of the bone on each side rises
almost perpendicularly, and terminates above in two processes
the anterior of which is the highest, is thin and pointed, and is
called the Coronoide Process. The anterior edge of this pro-
cess forms a ridge, which goes obliquely downward and forward
on the Jaw, upon the outside of the posterior sockets. To this
process the Temporal Muscle is attached ; and as it rises above
the center of motion, that Muscle acts with nearly equal ad-
vantage in all the different situations of the Jaw.
The Posterior Process, which is made for a moveable articu-
lation with the head, runs upward, and a little backward ; is
narrower, thicker, and shorter, than the anterior ; and termi-
nates in an oblong rounded head,(j) or Condyle, whose longest
axis is nearly transverse. The Condyle is bended a little for-
ward : is rounded, or convex, from the fore to the back part
and likewise a little rounded from one end to the other, or from
right to left, (k) Its external end is turned a little forward, and
(J) [In all animals which suckle their young, the condyle is convex or
flat, never concave. In birds and reptiles, the articular surface is con-
cave. These characters are of the greatest value to the palaeontologist
in the determination of fossil remains.]
(k) [The shape of the articulating condyle in the human mandible con-
trasts with the configuration of the same process in the highest known
Ape (Troglodytes Gorilla). In Man the thickest and most prominent
In the Gorilla, the
part of the process is near the middle of the joint.
inner end of the articulating condyle is the larger, and the posterior
border of the articulating surface wants that abrupt definition which is
usually observed in Man. In this latter respect the Chimpanzee (Troy,
niyer) makes a nearer approach to the human conformation.
(1)]
(1) Vide Owen on the Osteology of the Chimpanzees and Orangs, Zool.
Trans., vol. iv., p. 89.
OF THE LOWER-JAW.
the Upper-Jaw, have more fangs than those that correspond
with them in the lower, and the sockets are accordingly more
irregular. The Alveolar Process of the Upper-Jaw, is a section
of a larger circle than that of the lower, especially when the
Teeth are in the sockets. This arises chiefly from the anterior
Teeth in the Upper-Jaw being broader and flatter than those in
the Lower. The posterior part of the bone on each side rises
almost perpendicularly, and terminates above in two processes
the anterior of which is the highest, is thin and pointed, and is
called the Coronoide Process. The anterior edge of this pro-
cess forms a ridge, which goes obliquely downward and forward
on the Jaw, upon the outside of the posterior sockets. To this
process the Temporal Muscle is attached ; and as it rises above
the center of motion, that Muscle acts with nearly equal ad-
vantage in all the different situations of the Jaw.
The Posterior Process, which is made for a moveable articu-
lation with the head, runs upward, and a little backward ; is
narrower, thicker, and shorter, than the anterior ; and termi-
nates in an oblong rounded head,(j) or Condyle, whose longest
axis is nearly transverse. The Condyle is bended a little for-
ward : is rounded, or convex, from the fore to the back part
and likewise a little rounded from one end to the other, or from
right to left, (k) Its external end is turned a little forward, and
(J) [In all animals which suckle their young, the condyle is convex or
flat, never concave. In birds and reptiles, the articular surface is con-
cave. These characters are of the greatest value to the palaeontologist
in the determination of fossil remains.]
(k) [The shape of the articulating condyle in the human mandible con-
trasts with the configuration of the same process in the highest known
Ape (Troglodytes Gorilla). In Man the thickest and most prominent
In the Gorilla, the
part of the process is near the middle of the joint.
inner end of the articulating condyle is the larger, and the posterior
border of the articulating surface wants that abrupt definition which is
usually observed in Man. In this latter respect the Chimpanzee (Troy,
niyer) makes a nearer approach to the human conformation.
(1)]
(1) Vide Owen on the Osteology of the Chimpanzees and Orangs, Zool.
Trans., vol. iv., p. 89.
