54 2 A N A T 
the ofTa fpongiofa inferiora, by contaft; lienee there fre¬ 
quently is an intimate union of the fubftance of thefe bones 
in aged Ikulls; by the orbitar proeeffes, to the olfa plana 
and cellulae ethmoida?, by the ethmoid future ; to the 
bony of the fphenoid bone, by the fphenoid future; by 
the internal edge of the fquare bones, to each other by the 
longitudinal palate future; and by their nafal fpines, to 
the vomer, by the fpinous future. The palate-bones form 
part of the palate, nollrils, orbits, and foifce pterygoideae; 
and they cover part of the finus maxillares, fplienoidales, 
and ethmoidei. * When we are acquainted with the hiftory 
of thele bones, the reafon is evident, why the eyes are fo 
much afteded in ulcers of the palate, as to be often at¬ 
tended with blindnefs, .which frequently happens in an ill- 
managed lues venerea; or why, on the other hand, the 
palate fuffers from an atgylops. 
Of a turbinata, ox fpongiofa inferiora, refemble the fttpe- 
rior off a fpongiofa in fhape and fubftance, but have their 
anteriot and upper edges contiguous to the tranfverfe ridges 
of the nafal procelfes of the maxillary and palate bones. 
From their upper ftraight edge, two (mail procelfes (land 
out: the poflerior, w hich is the broadell, descends to cover 
fome of the antrum Highmorianum ; the anterior riles up 
to join 'die os unguis, and to make part of the lacrymal 
dud. The names of thefe bones fufficiently declare their 
Jpongy fubflance, which has no firm external plate cover¬ 
ing it. They are joined to the olfa maxillaria, palati, and 
unguis, in all fubjeds, by a firm union of fubftance; and, 
as this often happens in people of no great age, fome au¬ 
thors are of opinion, that they fhould be efteemed part of 
tiie palate-bones ; others think, that, fince their upper 
edge is continued by a plate to part of the os ethmoides, 
they ought to be efteemed part of this bone. Their ufe is, 
to ftraighten the rioftrils, to afford a large furface for ex¬ 
tending the organ of fmelling, to cover part of the antra 
nmxillaria, and to affift in forming the under part of the 
lacrymal duds, the orifices of which into the nofe are con¬ 
cealed by thele bones. 
Vomer , or bone refembling a plough-fhare, is the thir¬ 
teenth of the upper jaw, and is without a fellow, forming 
the lower and back parts of the partition of the nofe. 
The figure of this bone is an irregular rhomboid. Its fides 
are flat and fmooth. Its polterior edge appears in an ob¬ 
lique direction at the back-part of the noftrils. The upper 
one is firmly united to the bafe of the fphenoid bone, and 
to the nafal plate of the ethmoid ; and is hollow, for re¬ 
ceiving the procelfus azygos of the fphenoid. The ante¬ 
rior edge has a long furrow in it, where the middle car¬ 
tilage of the nofe enters. The lower edge is firmly united 
to the nafal fpines of the maxillary and palate bone. The 
vomer is convex at its upper part, and then is ftraight, as 
it is extended downwards and forwards, where it is com- 
pofed of two plates, the edges of which have a great num¬ 
ber of (mail procelfes, difpofed fomewhat like the teeth 
of a lav/, but more irregularly, and feveral of them are 
reflected back. Between thefe plates a deep folfa is left, 
which, as far as the top of the curvature, is wide, and 
has ftrong fides, for receiving the procelfus azygos of the 
fphenoid bone. Beyond the arch forwards, the folfa is gra¬ 
dually narrower and (hallower to the point of the bone, re¬ 
ceiving for fome way the nafal lamella ethmoidea; which, 
after the ofiification is complete, is fo clofely united to the 
vomer by the little procelles piercing its fubftance, as to 
prevent any reparation ; on which account it has been 
efteemed by fome authors a part of the ethmoid bone. The 
middle cartilage of the nofe fills up what remains of the 
fofla at its fore-part. The pofterior edge of the vomer, 
which appears above the back-part of the palate-bones, 
is broader above; but, as it delcends forwards, becomes 
thinner, though it is dill folid and firm. The lower edge 
of this bone, which reds on the nafal lpine of the palate 
and maxillary bones, has a little furrow on each fide of a 
filial 1 middle ridge, an fiver ing to the fpines of the bones of 
different fides, and the interfaces between them. This and 
the upper edge meet in the pointed fore-end of this bone. 
O M Y. 
It is joined above to the fphenoid and ethmoid bones, and 
to the middle cartilage of the nofe by fchindylelis; below, 
to the maxillary and palate bones by the fpinous future. 
The vomer divides the noftrils ; enlarges the organ of 
fmelling, by allowing place for expanding the merqbrane 
of the nofe on its fides ; and fuftains the palate-plates of 
the maxillary and palate bones, which otherwife might be 
in hazard of being prelfed into the noftrils. 
Maxilla inferior , the lower jaw, conlifts only of one 
moveable bone, and fixteen teeth incafed in it. This bone 
is fttuated at the lower part of the face, fo as its convex 
middle part is forward, and its legs are ftretched back. It 
is commonly divided into the chin, fides, and procelfes. 
The chin is the middle fore-part ; the extent of which to 
each fide is marked on the external furface by the holes 
©bfervable there, and internally by the beginning of an 
oblique ridge. Beyond thefe the fides appear ; and are 
continued till the; bone, by bending upwards, begins to 
form the procejfes. On the fore-part of the chin, a tranf¬ 
verfe ridge appears in the middle ; on each fide of which 
the mufeuli quadrati, or deprelfores, .and the levatores 
labii inferioris, deprefs the bone : and below thefe prints 
a fmall riling may be obferved, where the depreffores com¬ 
mence. On the back-part of the chin, fometimes three, 
always two, fmall protuberances appear in the middle. To 
the uppermoft, when it is feen, the frsenum of the tongue 
is connefted. From the middle one, the mufeuli genio- 
glolli rife; and from the lowed, the genio-hyoidei have 
their origin. Below the laft, we fee two rough finuofities 
formed by the digaftric mufcles. 
At the lower and fore part of the external furface of 
each fide of the lower jaw, a fmall eminence may be ob 
ferved, where the deprelfor labiorum communis riles. .Near 
the upper edge of the fide a ridge runs lengthwife, to which 
the under-part of the rnufculus buccinator is connected. 
Internally, towards the upper edge of each fide, another 
ridge appears, from which the mylo-hyoidei have their 
origin, and to which the internal membrane of the gums 
adheres. In the upper edge of both chin and fides, are a 
great many deep pits or fockets, for receiving the roots of 
the teeth. The number and magnitude of thefe fockets 
are various, becaufe of the different number, as well of 
the teeth thetnfelves, as of their roots, in different people. 
Thefe fockets in the lower jaw, as well as in the upper 
one, are lefs deep as old age comes on : when freed from 
the teeth by any means, they are fome time after filled up 
with an offeous net-work, which at laft becomes entirely 
folid, and as fmooth as any other part of the bone; fo 
that, in a great many old fubjeds, we cannot obferve a 
veftige of the fockets : but then the jaw becomes lefs, 
and much narrower. Idence we may know why the chin 
and nofe of edentulous people are much nearer than be¬ 
fore the teeth were loft ; while their lips either fall in to¬ 
wards their mouth, or (land prominent forwards. When 
new teeth are protruded, new fockets are formed. The 
lower edge of the chin and fides is fmooth and equal, and 
is commonly called the bafe of the lower jaw. 
The procejfes are two on each fide. The anterior fti3rp 
thin coronoid ones have the crotaphite mufcles inferted 
into them. The pofterior proeeffes or condyles terminate 
in an oblong fmooth head, fupported by a cervix. The 
fore-part of the root and neck of thefe condyloid proeeffes 
are a little hollow and rough where the external pteregoid 
mufcles are inferted. The holes of the lower jaw are two 
on each fide; one at the root of the proeeffes internally, 
where a large branch of the third branch of the fifth pair 
of nerves enters with an artery, and a vein returns. The 
other hole is external, at the confines of the chin, where 
branches of the nerve and veffels come out. The canal 
between thefe two holes is formed in the middle of the 
fubftance of the bone, and is pierced by a great number of 
fmall holes, by which the nerves and blood-veffels of the 
cancelli and teeth pals. This canal is continued-a little 
farther than the external hole at the chin. On account 
of the veffels and nerves in the lower jaw, fradures of it 
may 
