Lower jaw

“ The lower jaw fits the upper one, and when its teeth clench with those above, the cavity of the mouth is nearly shut, and it is quite closed by the lips and cheeks outside.
As might be expected from the great muscles which unite the lower jaw to the skull, it is large and strong, but it has no projecting chin, and this slopes in a retiring manner. The side of the jaw which supports the teeth is, as in man, curved upwards behind at what is called the angle. The jaw is very movable, and can act sideways in munching, or up and down, as in biting ”

“ The prolonged mouth-breathing imparts to adenoid patients a characteristic look in the face. The lower jaw is dropped and the lips are kept constantly apart. In many cases the upper lip is short, showing some part of the upper teeth. The dropping of the jaw draws upon the soft parts and tends to obliterate the natural folds of the face about the nose, lips, and cheeks. ”

“ The muscles attached to the lower jaw are of great strength; by their action alone, some persons are enabled to bite the hardest substances. By putting the fingers upon the side of the head above and in front of the ears, and upon the face above the angle of the jaw, while masticating food, the alternate swelling and relaxation of these muscles will be clearly felt. ”

“ Now, as I observed just now, there are several tall, athletic young men about, and also there are several men who have lost teeth. But now I saw that this tall and athletic young man had lost exactly two teeth—one from the lower jaw, just to the left of the centre, and another from the upper jaw, further still toward the left! Trivialities, pointing in the same direction, became important considerations. More, his teeth were irregular throughout, and, as nearly as I could remember it, looked remarkably like this little plaster mould of mine. ”

“ In these cases the suitable mode of reduction is apparent. For somebody must hold the patient’s head, another grasps the lower jaw internally and externally with his fingers at the chin, while the patient yawns as much as he can conveniently; and we must first move the jaw with the hand hither and thither for a certain time, and order the man to relax the jaw and separate it ”

“ Along with abscess of the gums, purulent matter often collects in the cellular tissue of the cheek or of the chin. In the latter situation, the inflammation and suppuration are often caused by the teeth in the front or side of the lower jaw being too much crowded together. When the teeth are crowded together, the patient, of course, cannot be effectually benefited till one or more of them are extracted, and sufficient space allowed for development of the others. ”

“ Where should be the nose, was seen only a blackened cavity—the cheek had sloughed off during life, and presented only a spongy and half decayed bone—around the eyes which were imperfectly closed, was a dark putrid line, while the throat was swollen, and what remained of the teeth of the lower jaw, were exposed to view, by the absence of the nether lip, which had perished as other portions of the face—yet reader, in that horrid visage she recognized her seducer. ”

“ In every case the teeth of the lower jaw bite within those of the upper, and, the jaws being so articulated as to allow only of up and down motion, and being incapable of play from side to side, the molars and premolars entirely lose their character of grinders, and become trenchant, cutting up the food, in fact, in precisely the same manner as a pair of scissors. ”

“ Still working along the lower jaw, come right up until you can cut out, just under the eye, the top end of the return. Leaving it attached by a thin membrane 'to the upper jaw, skin downward toward the nose, and, by undercutting and using great care, completely skin up to the nostril, which sever. Do precisely the same with the other side. The nostrils being completely skinned out, the skin holds just below them. ”

“ On the lower jaw the villiform teeth in front are more uniformly small, and there is an acute row of subulate teeth, which are tallest in the middle of the limbs of the jaw, beyond which, towards the corners of the mouth, there is an even row of very small teeth. At the end of the jaw there is a small canine on each side exterior to all the others. ”

“ It is most likely that no vertically directed tooth would be developed in the part of the jaw so occupied by the curved bases of the incisors, and hence a diastema or toothless space would intervene between the molars and incisors of this lower jaw, as in the upper jaw of the Toxodon. ”

“ The muscles which move the lower jaw are affected more early, and more obstinately than any of the other external muscles of the body, only because they are more constantly in a relaxed, or idle state. ”

“ The lower jaw runs back a long way and is then very pronounced—always a sign of animality, although in men of intellect and feeling this same quality may often be innocuous, and even useful as supplying energy; the mouth, especially when seen full-face, is very coarse, and the lips thick and heavy; the nostrils are very wide at their base, the ears are noticeably bad, and the eyes are light blue and as hard as a flint. ”

“ Glasse would say, between his teeth, which are in double rows upon each jaw, and directed backward that they may act more effectually, he first brings the victim to a suitable position—head first he prefers, then, leaving one set of teeth, say the lower, fixed, he advances the upper jaw, fixes its teeth into the skin, and leaves them there while he moves forward, the lower jaw, and so continues till the bird or frog is worked into his throat ”

“ In reducing the food, the teeth of the lower jaw move against those of the upper, while the food is held by the tongue and cheeks between the grinding surfaces. The front teeth are thin and chisel-shaped. ”

“ Having studied the jaws and examined the arrangement of the teeth, we should say a few words on the movements which the lower jaw is able to execute. In man, these movements are varied in character: the jaw is lowered and raised ”

“ Fig. 247. Fig. 248.
Author’s Method.
In some cases the ectropion, whether partial or more or less general, is caused by protrusion of the teeth either of the upper or lower jaw; more commonly of the alveolar structure of the superior maxillary bone. In such cases a cosmetic operation on the mucosa will do [188] little to restore the deformity. Such cases should be corrected primarily by a surgeon dentist, the teeth being forced back into place by proper metal springs or splints—a tedious process requiring from six months to two years’ time. ”

“ Each individual tooth, missing its best stimulus to healthy growth and vigor, firm and regular pressure and exercise against its fellow in the jaw above or below, gets a twist in its socket, wears away irregularly, and becomes an easy prey to decay, while from failure of the entire upper and lower arches of the teeth to meet squarely and press evenly and firmly against one another, the jaws fail to expand properly and the tendency to narrowing of the tooth-arches and upward vaulting of the palate is increased. ”

“ The eye has almost disappeared under the brow, the mouth is tightly closed to a degree that is quite unpleasant and there is a deliberate exaggeration of a slight defect he actually had—a tendency for the lower jaw to protrude a little. ”

“ Larger size of M. pseudotemporalis profundus, the muscle that functions simultaneously as an adductor of the lower jaw and retractor of the upper jaw, in the White-winged Dove was the character found in the jaw musculature that could be used to support the contention that Zenaidura and Zenaida represent distinct genera. Larger size of this muscle in the white-wing seems to be related to its elongated beak. The long beak apparently is used for nectar-feeding in flowers of the Saguaro Cactus. ”

“ The lower eye-teeth, finding nothing to rub against, grow to a surprising size, first upward, then down, until they again reach the jaw, grow on and on, through the cheek, through the jaw-bone, pushing out a few other teeth en passant, then they come out of the jaw again, and curve a second, sometimes a third time, if the poor beast lives long enough. ”

“ The teeth are large, white and strong. In old age they appear much ground down; particularly is this the case with women, who chew the different kinds of fibres, of which they make nets and bags. The lower jaw is heavy ”

“ When the second division of the nerve is affected the pain is chiefly in the cheek and upper jaw, the painful points being immediately below the lower eyelid, over the cheek bone, and about the upper lip. ”

“ The habits are very dirty and help to spread infections. The baby may swallow air while practicing them, with colic as a result, and he may so deform the shape of his upper jaw that, later in life, the upper and lower teeth will not meet as they should when he masticates ”