Those which transmit blood vessels are; 1, canales caroctici : 2, f spinosa : 3, f. lacera in basi cranii : 4, f. magnum.
Bones of the fare--The ossa nasi con stitute the arch of the nose. The ossa lacrymalia or unguis are placed flt the fore part of the inner edge of the orbits, and contain an excavauon which holds the lacryrnal bag.
The ossa malarum form the prominen ces of the cheeks.
The ossa naaxillaria superiom form the largest portion of the upper jaw, and most of the bony palate, or roof of the mouth ; they contain also the upper teeth.
The ossa palati form tho back part of the bony palate.
The ossa turbinata inferioraare situat ed in the cavity of the nose.
The former completes, with the nasal portion of the ethmoid, the septum that divides the two nostrils.
The maxilla inferior is articulated to the basis cranii, and holds the lower teeth. The bones of the cranium and face compose the two orbits, or pyramidal bo ny cavities, holding the °trans of vision ; to each of these, seven bones contribute. They also form the cavity of the nose, which is very extensive, and includes portions of nearly all the bones of the face, and some of the skull. It has va rious cells, formed in the bones of the skull and face, opening into it.
The terth.—Thesc organs are composed internally of a very hard bony substance ; stnd are covered externally by a still hard er matter, called the cortex or enamel. Each tooth has a body or crown, which is the part seen in the mouth ; a neck, round which the gum adheres; and one or more fangs or roots, which are sunk in a process of the jaw, called the alveolar. These bodies are not formed in a nidtis of cartilage, like bones, but on a soft vascular body, called a pnlp, which may be compared to the core, on which aliorn is formed. This is surrounded by a deli cate membrane, called the capsule of the tooth. When the teeth are being formed, these pulps and capsules, with the rudi ments of the teeth, arc lodged in cavities hollowed out of the jaw bone. They af terwards rise, and, piercing the gum, ap pear in the mouth.
Teeth differ from other bones in pos sessing no vessels nor ners-es in their sub stance. As they are destined for the
merely mechanical function of triturating the food, such ptuts A ould not have been suitable to this office. The pain of tooth ach arises from a nerve, which, with a vessel, resides in a hollow, formed in the centre of the fang and body of each tooth. These parts are exposed by the decay. 1'he teeth, in consequence of possessing no vessels, are only affected by chemical and mechanical causes. They do not repair the effects of trituration, nor of accidental injury; nor do they suffer from any of the diseases which affect other bones.
There are two sets of teeth; the first are fewer in number, and smaller in size; a.s they fall out at a certain age, to make room for other larger ones, they are call ed deei &loos or temporary. The second set lasts throughout life, and are called the adult or permanent set The latter consists of 32 teeth ; 16 in each jaw. There are four ineisores or cutting teeth in front ; 2 canini or cuspi dati,- or dog teeth, placed one on each side of the former ; 4 bicuspides behind, the last; and 6 molares behind these. From the late period at which the last molaris appears, it is called the dens sa pientia, or wise tooth.
The temporary set consists of twenty teeth ; ten In each jaw. There are 4 in cisores ; 2 cuspidati ; and 4 molares.
The perma.nent teeth are lodged at first in cavities of the jaw, near the roots of the temporary- ones ; and, as these last are shed, rise up to supply their places.
The bone of the tongue is called os hyoides, from its very accurate resem blance to the Creek u. It consistsofa body, two cornua, and two appendices, which are in fact so many separate bits of bone.
The bones of the trunk consist of those of the spine, thorax, and pelvis.
The spine consists of twenty-four true or moveable vertebra ; an os sacrum, and an os coccygis (which indeed is compo sed of four 'pieces) ; these last bones, bearing considerable resemblance to the vertebra, are called sometimes the false vertebra.