The principles and practice of dentistry : including anatomy, physiology, pathology, therapeutics, dental surgery and mechanism / by Chapin A. Harris.

  • Harris, Chapin A. (Chapin Aaron), 1806-1860.
Date:
1906
Catalogue details

Licence: Public Domain Mark

Credit: The principles and practice of dentistry : including anatomy, physiology, pathology, therapeutics, dental surgery and mechanism / by Chapin A. Harris. Source: Wellcome Collection.

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    behind. But the shape of this cavity is exceedingly variable. In -examining a collection of nearly one hundred maxillae in the Dental Department of the University of Maryland, no two sinuses were found to be shaped alike; and this difference is as marked between the right and the left in the same, as in different subjects. The floor of some is nearly flat, but in the majority of cases it is very uneven ; some¬ times crossed by a single septum, varying from one-eighth to half an inch in height; at other times there are found three or four septa, dividing the lower part of the cavity into as many separate compart¬ ments, with the bottom or floor of no two on a level with each other. Some are perforated by the roots of one or more teeth ; at other times the roots of several teeth extend considerably above the level of the floor of the antrum, covered by a lamina of bone scarcely thicker than bank-note paper. In other cases, the floor of the antrum is half an inch above the extremities of the roots of the teeth. This cavity also varies as much in size as it does in shape. The opening of the antrum is, on its nasal portion or base, into the middle meatus of the nose; in the skeleton it is large, while in the natural state it is much contracted by the ethmoid bone above, the inferior turbinated bone below, the palate bone behind, and by the mucous membrane which passes through the opening and lines the interior of the antrum. A deep groove lies in front of the opening in the antrum, which is converted into a canal for the nasal duct by the lachrymal and inferior turbinated bones. The Malar Process is a rough, triangular process, marking the boundary between the external and internal surfaces. It presents on its upper margin a roughened surface for articulation with the malar bone. The Nasal Process forms the lateral boundary of the nose. It is a thick, triangular prominence articulating at its upper extremity, by a serrated edge, with the frontal bone, and, by an uneven surface, with the ethmoid bone; a little lower on its internal surface it offers a trans¬ verse ridge, the superior turbinated crest, for articulation with the middle turbinated bone; below this is the inferior turbinated crest, to which is attached the inferior turbinated bone; and lying between these crests is a smooth, concave space, forming part of the middle meatus, while beneath the inferior crest is a like space which forms part of the inferior meatus. By its anterior border it is articulated with the nasal bone, and by its posterior with the lachrymal bone, forming with it the canal for the nasal duct, while at the junction of the anterior lip of the nasal groove with the orbital surface is placed the lachrymal tubercle, serving as a guide to the duct in all operations for fistula lachrymalis.