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BONES. —
89
from the facial surface to the posterior portion of the palate process
the premaxilla does not unite with the parts containing the other teeth,
neither do the true maxillre and palatal processes of the palate bones
unite. In double cleft palate the incisorial divisions may have united
in the median line (forming an intermaxillary bone), but not laterally
Fig. 38.
J Jot Nascbl ^
Taeial ^ort.V?
1 for Orbital lip
Malar j'ort^^
Anterior Surface.
at
Birth
1 fur Incistvt Jtort
I for Palatal jiorr^
Development of the Superior Maxillary Bone, by four centres.
with the true maxillae. In some of these cases the vomer can be seen
protruding in the median line between the two halves of the hard palate.
The alveolar process is developed as a special support for the teeth.
At birth it is represented by the walls of a deep groove, in which
the deciduous and the germs of the permanent teeth are situated.
As the teeth grow the alveolar process advances, until it encases them.
Just prior to the shedding of the deciduous teeth their roots and tlieir
bony processes are absorbed, and the latter are re-formed on the ai)pear-
ance of the permanent teeth. This process again commences to disap-
pear on the loss of the second set of teeth, and in time may be wholly
removed. In certain diseased conditions of the bones this process dis-
appears to some extent before the permanent teeth are lost ; and this
bone-absorption may go on until teeth otherwise healthy become loose
and drop out.
The Maxillary ShxuH (antrum of Highmore) is the large air-cavity
situated in the body of the bone. It is irregularly pyramidal in shape,
the apex bearing toward the malar bone, into which it may extend, and
its base toward the nasal cavity. Its development is similar to the
sinuses in the frontal bone, and like them is not completed until after
the age of puberty, although it makes its apj^earance as early as the
fifth or sixth month of foetal life. Hence in early life the surrounding
BONES. —
89
from the facial surface to the posterior portion of the palate process
the premaxilla does not unite with the parts containing the other teeth,
neither do the true maxillre and palatal processes of the palate bones
unite. In double cleft palate the incisorial divisions may have united
in the median line (forming an intermaxillary bone), but not laterally
Fig. 38.
J Jot Nascbl ^
Taeial ^ort.V?
1 for Orbital lip
Malar j'ort^^
Anterior Surface.
at
Birth
1 fur Incistvt Jtort
I for Palatal jiorr^
Development of the Superior Maxillary Bone, by four centres.
with the true maxillae. In some of these cases the vomer can be seen
protruding in the median line between the two halves of the hard palate.
The alveolar process is developed as a special support for the teeth.
At birth it is represented by the walls of a deep groove, in which
the deciduous and the germs of the permanent teeth are situated.
As the teeth grow the alveolar process advances, until it encases them.
Just prior to the shedding of the deciduous teeth their roots and tlieir
bony processes are absorbed, and the latter are re-formed on the ai)pear-
ance of the permanent teeth. This process again commences to disap-
pear on the loss of the second set of teeth, and in time may be wholly
removed. In certain diseased conditions of the bones this process dis-
appears to some extent before the permanent teeth are lost ; and this
bone-absorption may go on until teeth otherwise healthy become loose
and drop out.
The Maxillary ShxuH (antrum of Highmore) is the large air-cavity
situated in the body of the bone. It is irregularly pyramidal in shape,
the apex bearing toward the malar bone, into which it may extend, and
its base toward the nasal cavity. Its development is similar to the
sinuses in the frontal bone, and like them is not completed until after
the age of puberty, although it makes its apj^earance as early as the
fifth or sixth month of foetal life. Hence in early life the surrounding
