DOI Page / Citation link:
https://doi.org/10.11588/diglit.6271#0039
( 13 )
FCETAL CRANIUM.
The bones of the skull of a fetus at birth, are far more nu-
merous than those of an adult; for many of the processes of
the latter are epiphyses in the former; thus the occipital bone
consists of four portions ; the sphaenoidal of three,&c. There
are no sutures in the cranium of the fetus. The parietal
bones, and the frontal bones, do not coalesce until the third
year, so that before that period there is an obvious interstice,
commonly called mould, and scientifically the fontanel, or
fons pulsatilis. There is also a lesser space, occasionally, be-
tween the occipital and parietal bones, termed the posterior
fontanel. These spaces between the bones are filled up by
the dura mater, and the external integuments, so that, during
birth, the size of the head may be lessened ; for at that time
the bones of the head, upon the superior part, are not only
pressed nearer to each other, but they frequently lap one o ver
another, to diminish the size during the passage of the head
through the pelvis.
In the bones of the fetal cranium, the fibres are seen
diverging from a central point of ossification towards
the circumference, and each bone appears to be com-
posed of a single lamina ; so that ossification is goin<*
on fro;n a considerable number of points at the same
time, and the bones consequently approach e;:ch other
in the same proportion. After birth, the bones acquire
gueater thickness, and are soon observed to be com-
posed of two laminaB of fibres, each of which laminae
are connected by the spongy part, called the. diploe.
These laminae soon become the two tables of the cra-
nium, and as the bones join each other, their edges
become mutually indented, so as to form the different
sutures.
FCETAL CRANIUM.
The bones of the skull of a fetus at birth, are far more nu-
merous than those of an adult; for many of the processes of
the latter are epiphyses in the former; thus the occipital bone
consists of four portions ; the sphaenoidal of three,&c. There
are no sutures in the cranium of the fetus. The parietal
bones, and the frontal bones, do not coalesce until the third
year, so that before that period there is an obvious interstice,
commonly called mould, and scientifically the fontanel, or
fons pulsatilis. There is also a lesser space, occasionally, be-
tween the occipital and parietal bones, termed the posterior
fontanel. These spaces between the bones are filled up by
the dura mater, and the external integuments, so that, during
birth, the size of the head may be lessened ; for at that time
the bones of the head, upon the superior part, are not only
pressed nearer to each other, but they frequently lap one o ver
another, to diminish the size during the passage of the head
through the pelvis.
In the bones of the fetal cranium, the fibres are seen
diverging from a central point of ossification towards
the circumference, and each bone appears to be com-
posed of a single lamina ; so that ossification is goin<*
on fro;n a considerable number of points at the same
time, and the bones consequently approach e;:ch other
in the same proportion. After birth, the bones acquire
gueater thickness, and are soon observed to be com-
posed of two laminaB of fibres, each of which laminae
are connected by the spongy part, called the. diploe.
These laminae soon become the two tables of the cra-
nium, and as the bones join each other, their edges
become mutually indented, so as to form the different
sutures.