DOI Page / Citation link:
https://doi.org/10.11588/diglit.20658#0046
32
ANATOMY.
The ossa palati are situated at the back of the roof of the mouth.
The vomer is a single bone, deriving its name from its resemblance to a ploughshare. It serves
to support the middle cartillage of the nose ; and forms part of the septum narium, by dividing
the back part of the nose into two nostrils.
The ossa spongiosa inferiora are a kind of spongy amella, situated in each nostril, and united
to the spongy lamina of the ethmoid bone.
The maxilla inferior, or lower jaw, is somewhat of the shape of a horse-shoe. It may be con-
sidered as one bone, though in the foetus it consists of two. The upper edge of this bone, like thai
of the os maxil!are superius, has an alveolar process, furnished with sockets for the teeth. The
posterior part of this bone, on each side, rises nearly perpendicularly into two processes: the highest
is called the coronoid process, is pointed and thin, and receives the temporal muscles; the
other, called the condyloid process, is shorter and thicker, the ends somewhat rounder, and re-
ceived into a fossa of the temporal bone, and thereby fitted for a moveable articulation: this
joint is furnished with a moveable cartilage. The bone of the lower jaw is capable of a great va-
riety of motion ; horizontally forwards, lateral, and vertical.
The teeth are also bones, but of a particular structure, formed principally for mastication ; they
are of use also in the modulation of the voice. Their number in both jaws, at the age of full ma-
turity, is generally from twenty-eight to thirty-two. They are divided into three classes, viz. inei-
sores, canini, and grinders or molares. The incisores arc those four teeth, situated in the front of
each jaw: they receive their name from their use in dividing of food: they have two surfaces, the
anterior, which is convex, and the posterior, which is slightly concave. Those in the upper are in
general broader than those in the other jaw: and by being placed somewhat obliquely they usually
fall over the latter: the canini, or dog-teeth, derive their name from their resemblance to the teeth
of that animal: they are longer than the other teeth, in number four, one on each side of the inci-
sores in each jaw : they are narrower than the incisores, and terminate in a point. The molares, ^
or grinders, so called from their use in grinding the food, are ten in number, in each jaw. The
two first, or those nearest the canine teeth, on each side, differ from the other three, and seem to be
of a middle nature between the incisores and the larger molares. The two next are much larger.
The fifth, or last, on each side, is smaller and shorter than the rest, and seldom makes its appear-
ance till after the age of twenty. The incisores, canine teeth, and the two first molares, on each
side in each jaw, are called temporary or milk teeth, being generally all shed between the age of
seven and fourteen, when they are succeeded by others called the permanent or adult teeth, which
are of a firmer texture, and have larger fangs. The other twelve teeth, viz. three grinders on each
side, are added in after-age ; when the jaw gradually lengthens in growth to make room for them.
This increase in the length of the jaw is the reason why the face is more round and flat in children
than in adults. When the teeth fall out through age, the alveoli fill up, the chin then projects
forward, and consequently the face is much shortened.
The os hyoides is a bone placed at the root of the tongue, and may be felt at the fore part of
the throat. Its uses are to support the tongue, and afford attachment to several muscles, many
of which belong to that member.
• 2. The trunk consists of the spine, thorax, and the pelvis.
The spine, called vertebra, consists of a great number of bones, forming a long bony column,
somewhat bent at each end, and is generally described as like the letter/. It extends from the
head
ANATOMY.
The ossa palati are situated at the back of the roof of the mouth.
The vomer is a single bone, deriving its name from its resemblance to a ploughshare. It serves
to support the middle cartillage of the nose ; and forms part of the septum narium, by dividing
the back part of the nose into two nostrils.
The ossa spongiosa inferiora are a kind of spongy amella, situated in each nostril, and united
to the spongy lamina of the ethmoid bone.
The maxilla inferior, or lower jaw, is somewhat of the shape of a horse-shoe. It may be con-
sidered as one bone, though in the foetus it consists of two. The upper edge of this bone, like thai
of the os maxil!are superius, has an alveolar process, furnished with sockets for the teeth. The
posterior part of this bone, on each side, rises nearly perpendicularly into two processes: the highest
is called the coronoid process, is pointed and thin, and receives the temporal muscles; the
other, called the condyloid process, is shorter and thicker, the ends somewhat rounder, and re-
ceived into a fossa of the temporal bone, and thereby fitted for a moveable articulation: this
joint is furnished with a moveable cartilage. The bone of the lower jaw is capable of a great va-
riety of motion ; horizontally forwards, lateral, and vertical.
The teeth are also bones, but of a particular structure, formed principally for mastication ; they
are of use also in the modulation of the voice. Their number in both jaws, at the age of full ma-
turity, is generally from twenty-eight to thirty-two. They are divided into three classes, viz. inei-
sores, canini, and grinders or molares. The incisores arc those four teeth, situated in the front of
each jaw: they receive their name from their use in dividing of food: they have two surfaces, the
anterior, which is convex, and the posterior, which is slightly concave. Those in the upper are in
general broader than those in the other jaw: and by being placed somewhat obliquely they usually
fall over the latter: the canini, or dog-teeth, derive their name from their resemblance to the teeth
of that animal: they are longer than the other teeth, in number four, one on each side of the inci-
sores in each jaw : they are narrower than the incisores, and terminate in a point. The molares, ^
or grinders, so called from their use in grinding the food, are ten in number, in each jaw. The
two first, or those nearest the canine teeth, on each side, differ from the other three, and seem to be
of a middle nature between the incisores and the larger molares. The two next are much larger.
The fifth, or last, on each side, is smaller and shorter than the rest, and seldom makes its appear-
ance till after the age of twenty. The incisores, canine teeth, and the two first molares, on each
side in each jaw, are called temporary or milk teeth, being generally all shed between the age of
seven and fourteen, when they are succeeded by others called the permanent or adult teeth, which
are of a firmer texture, and have larger fangs. The other twelve teeth, viz. three grinders on each
side, are added in after-age ; when the jaw gradually lengthens in growth to make room for them.
This increase in the length of the jaw is the reason why the face is more round and flat in children
than in adults. When the teeth fall out through age, the alveoli fill up, the chin then projects
forward, and consequently the face is much shortened.
The os hyoides is a bone placed at the root of the tongue, and may be felt at the fore part of
the throat. Its uses are to support the tongue, and afford attachment to several muscles, many
of which belong to that member.
• 2. The trunk consists of the spine, thorax, and the pelvis.
The spine, called vertebra, consists of a great number of bones, forming a long bony column,
somewhat bent at each end, and is generally described as like the letter/. It extends from the
head