The principles of anatomy and physiology applied to the preservation of health / by Joseph Brown Walker.
- Walker, Joseph Brown
- Date:
- 1844
Licence: Public Domain Mark
Credit: The principles of anatomy and physiology applied to the preservation of health / by Joseph Brown Walker. Source: Wellcome Collection.
Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)
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![[4] tensive motion is secured. The fabric resulting from the connection of all these pieces in their natural order of arrangement, is called the Skeleton. The number of bones in the human skeleton is about 250, divided by anato- mists into those of the head, trunk and extremities. The bones of the cranium or skull are eight in number, viz : the frontal or bone of forehead, twe parietal or wall bones, one occipital or back bone of the head, two temporal bones situated before and above the ears, one ethmoid and one sphenoid bone situated in the internal part of the head ; all of which surround and form a complete protec- tion for the brain from all ordinary accidents, and also to the organs of hearing, seeing smelling and tasting. Pro- tection and not motion being the sole object of its con- struction, the numerous bones of which it is composed are joined to each other, not by movable joints like other bones, but by a kind of dovetailing, which combines the solidity of continuous structure with the advantages which their separation gives in facilitating growth, and prevent- ing the extension to all the injuries inflicted on one. The bones of the face are fourteen in number; consisting of two superior maxilary or upper jaw bones, one inferior maxilary or lower jaw bone, two malar or check bones, and several smaller bones which it would be unintelligi- ble to the general reader to attempt to explain. There are eight small bones belonging to the ears four on each, side, one at the root of the tongue called the os hyoides, and thirty-two dentas or teeth. The four front teeth in each jaw are called the incisor or cutting teeth, the two next on each side of the face in both jaws the cuspidati or sharp-pointed teeth, the two upper of which are vulgarly called the eye teeth, and the remaining twenty the mo lares or grinders. Each tooth may be divided into two parts, viz. its body, or that which appears above the gums and its fang, or root, which is fixed in the socket. Every tooth is composed of its enamel, its internal or bony substance. The enamel is the hard white substance which surrounds the body of the tooth. When broken it appears fibrous or striaeted ; and all the striae are di- rected from the circumference to the centre of the tooth.](https://iiif.wellcomecollection.org/image/b21161859_0004.jp2/full/800%2C/0/default.jpg)
