148 OSTEOLOGY. 
septum of the nose. Often deflected to one or other side, it divides the cavity of 
the nose (cavum nasi) into a right and left half. Projecting into these chambers 
from their outer walls can be seen the inner surfaces and free borders of the middle 
(concha media) and inferior (concha inferior) turbinated bones, the spaces below 
and between which form the inferior and middle meatuses of the nose respectively. 
Below the orbit, and to the outer side of the nasal aperture, the anterior or 
facial surface of the body of the superior maxilla (corpus maxillee) is seen; this is 
continuous inferiorly with the outer surface of the alveolar process (process alveo- 
laris), in which are embedded the roots of the upper teeth. 
A horizontal line drawn round the jaw on the level of a point midway between 
the lower border of the nasal aperture and the alveolar edge corresponds to the 
plane of the hard palate. Below that the alveolar process separates the cavity of 
the mouth from the front of the face; whilst above, the large air space, the maxil- 
lary sinus (sinus maxillaris), or antrum of Highmore, lies within the body of the 
superior maxilla. 
The malar or cheek bone (os zygomaticum) forms the lower half of the outer, 
and outer half of the lower border of the orbit. Its outer aspect corresponds to the 
point of greatest width of the face, the modelling of which depends on the flatness 
or projection of this bone. 
When the lower jaw (mandibula) is in position, and the teeth in both jaws are 
complete, the lower dental arch will be seen to be smaller in all its diameters than 
the upper, so that when the jaws are closed the upper teeth slightly overlap the 
lower both in front and at the sides. Exceptionally a departure from this arrange- 
ment is met with. 
NorMaA LATERALIS. 
Viewing this aspect of the skull, in the first instance, without the lower jaw, it 
is seen to be formed in part by the bones of the cranium, and in part by the bones 
of the face. A line drawn from the fronto-nasal suture to the tip of the mastoid 
process serves to define roughly the boundary between these portions of the skull. 
Of ovoid shape, the cranium is formed above by the frontal, parietal, and occipital 
bones from before backwards; whilst below, included within these are the sphenoid 
and temporal bones. The sutures between these several bones are arranged as 
follows :—Commencing at the external angular process of the frontal, the suture 
between that bone and the malar is first seen ; tracing this backwards and a little 
upwards, the lower edge of the frontal next articulates with the upper margin of the 
great wing of the sphenoid for a distance varying from three-quarters of an inch to 
one inch. Here the posterior border of the frontal turns upwards and slightly back- 
wards, forming with the parietal the coronal suture (sutura coronalis). The lower 
border of the parietal bone, which is placed immediately behind the frontal, articulates 
anteriorly with the hinder part of the upper edge of the great wing of the sphenoid. 
The extent of this suture (sutura spheno-parietalis) is liable to very great indi- 
vidual variation—at times being broad, in other instances being pointed and 
narrow, whilst occasionally the parietal does not articulate with the sphenoid at all. 
Behind the spheno-parietal suture the parietal articulates with the squamous part 
of the temporal (sutura squamosa). This repeats to a certain extent the curve 
formed by the outline of the calvaria, and ends posteriorly about one inch behind 
the external auditory meatus. Here the suture alters its character and direction, 
and in place of being scaly, becomes toothed and irregular, uniting for the space of 
an inch or so the posterior inferior angle of the parietal with the mastoid process 
of the temporal bone. This suture (sutura parieto-mastoid) is more or less hori- 
zontal in direction, and lies in line and on a level with the upper border of the 
zygomatic arch. Ata point about two inches behind the external auditory meatus 
the posterior border of the parietal bone turns obliquely upwards and backwards, 
and forms with the tabular part of the occipital bone the strongly-denticulated 
lambdoid suture (sutura lambdoidea). Inferiorly this suture is continued obliquely 
downwards between the occipital bone and the hinder border of the mastoid portion 
of the temporal, where it forms the occipito-mastoid suture (sutura occipito- 
