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 162 A N. A T O M Y. Part I. they are joined; but, as it afcends, Toon divides into Thefe bones form the greater part of the nofe and of two, three, or fometimes more holes; Tome of which the .roof of the mouth, and a conliderable fliare of the open into each noftril. Through them fmall arteries and prbit. They contain fixteen teeth, give rife to mufcles, veins, and a twig of the fecond branch of the fifth pair of tranfmillion to nerves, isc. as mentioned in the defcripnerves pafs, and make a communication between, or join tion of their feveral parts. the lining coats of the nofe and mouth. Ossa Palati are commonly defcribed as two fmai! The firft common hole is that, which appears at the fquare bones, at the back-part of the palate or roof of inner fide of the back-part of the tuberofity and of the the mouth, though they are of much greater extent, fockets of the teeth, and is formed by a fplfa in this jjeing continued up the back-part of the noffrils to the bone, and a correfponding one in the os palati: through orbit. Each palate-bone may therefore be divided into it a nerve, which is a branch of the fecond branch of four parts, the palate fquare bone, the pterygoid pro? the fifth pair, runs to the palate. The other com- cefs, nafal lamella, and orbitar procefs. mon hole is the great flit in the outfide of the orbit de- The fquare bone is unequally concave, for enlarging fcribed already, as the fecond common hole of the fphe- both the mouth and cavity of the nofe. The upper part of its internal edge rifes in a fpine,. after the fame mannoid bone. All the body of the maxillary bone is hollow, and ner as the.palate-plate of the maxillary bone does, to be leaves a large finus akin to the frontal and fphenoid, joined with the vomer. Its anterior edge is unequally which is commonly, but unjuflly, called antrum High- ragged, for its firmer connexion with the palate-procefs morianum.—At the bottom of this cavity, we may oft- of the os maxillare.-—The internal edge is thicker than en obferve feme protuberances, in which the fmajl points the reft, and of an equal furface, for its conjunction with of the roots of the teeth are contained.—This cavern its fellow of the other fide. Behind, this bone is and the fockets of the teeth are often divided by the in- fomewhat in form of a crefcent, and thick, for the firm terpofition only of a very thin bony plate, which is lia- connedtion of the velum pendulum palati; the internal ble to be eroded by acrid matter colledled in the antrum, point being produced backwards, to afford origin to the or to be broke in drawing a tooth. The fymptdms of a palato-ftaphyiinus, or azygos-mufcle. This fquare colle&ion of a matter here naturally lead us to the prac- bone is well diftinguiftied from the pterygoid procefs by a tice of pulling out the teeth, and piercing through this perpendicular foffa, which, applied to fuch another in plate into the antrum, to procure an evacuation of the the maxillary bone, forms a pafiage for the palatine branch of the fifth pair of nerves; and by another fmall collefted matter. The maxillary finufes have the fame ufes as the fron- hole behind this, through which a twig of the fame nerve tal and fphenoidal; and the fituation of the. finufes is paffesi fuch, that the liquor drilling from them, from the cells The pterygoid procefs is fomewhat triangular, having of the ?>.hmoid and palate-bones, and from the lacrymal a broachbafe, and ending fmaller above. The back-part tiudls, may always moiften all the parts of the membrane of this procefs has three foffae formed in it; the two laof the nares in the different fituations which the head teral receive the ends pf the two plates of the fphenoid bone, that are commonly compared to a bat’s wing; the is in. The fubflance of the ofla maxillaria is compaft and middle fofia makes up a part of what is commonly called the foJ)'a pterygoidea ; the fore-lide of this palatine ptefirm, except at the inferior proceffes, in which the teeth rygoid procefs is an irregular concave, where it receives are lodged, where it is very fpcngy. The maxillary bones are joined above by the upper the back-part of the great tuberofity of the maxillary ends of their nafal procefles to the os fronds, by the bone. -frequently feveral fmall holes may be obferved tranfverfe future;—at the fides of thefe procefl’es, to the in this triangular procefs, particularly one near the mid- • ofla unguis, by the lacrymal futuresto the nafal bones, die of its bafe, which, a little above, communicates with common and proper holes of this bone already taken by the lateral nafal futures;—by their orbitar procefies, the to the cheek-bones, by the external orbitar futures;— notice of. The nafal lamella of this bone.is extremely thin and by the internal fides of the internal orbitar proceffes, to brittle, and rifes upwards from the upper fide of the exthe ofla plana, by part of the ethmoidal future;—by the back-part of the tuberofities, to the palate bones, ternal edge of the fquare bone, and from the narrow extremity of the pterygoid procefs; where it is fo weak, by the futuras palato-maxillares;—by the pofferior edges and at the fame time fo firmly fixed to the maxillary of their palatine lamella;, to the offa palati, by the tranfverfe palate-future;—by their nafal fpines, to the bone,- as to be very liable to be broken in feparating the vomer, by the fpinous future;—by their fockets, to the bones. From the part where the plate rifes, it runs of the tuberofity of the maxillary teeth by gomphofis ;—by the internal edge of the palate- up broadto onformthe ainfide confiderable fhare of the fides of the plate, to one another, by the longitudinal palate-future ; bone, finus, and to clofe up the fpace between the on the upper and fore-part of which a furrow is left for maxillary receiving the cartilage which forms the partition of the fphenoid and the great bulge of the maxillary bone, where there would otherwife be a large flit opening into noftrils; -— between the fore-part of the noftrils and the From the middle internal fide of this thin mouth, to each other, by the myftachial future; — plate,noftrils. a crofs ridge, placed on fuch another of the maxilfametimes they are connected to the offa fpongicfa infelary bone, is extended; on it the back-partfpongiofum of the os riora, by a plain concretion or union of fubffance.