ANATOMY. 



219 



orbit and edge of the cheek; the internal orbi- 

 tary, which also forms a part of the orbit ; the 

 maxillary, by which it is joined to the superior 

 maxillary bone, and the zygomatic process, which is 

 joined to the temporal bone, to form the zygoma 

 or cavity under the zygomatic process of that bone 

 transmitting the tendon of the temporal muscle 

 like a yoke; and hence its name. Every part of the 

 cheek bones is formed at birth, but the shape is 

 rather more than triangular, and becomes gradually 

 changed. Four muscles are attached; the obliquus, 

 inferior oculi, zygomaticus, major and minor mas- 

 seter, while the orbicularis palpebrarum covers it. 



Ossa Maxillaria Superiora, or the Upper Jaw 

 Bones, (No. 9. tig. 1.) The superior maxillary bone, 

 at birth, consists of one portion, so that every pro- 

 cess and cavity can be seen, but not so perfect 

 as in the adult, where the superior maxillary con- 

 sists of two hollow bones, situated in the anterior 

 and middle part of the face, which assist in forming 

 the nose, orbit and palate, so that their shape is 

 very irregular. Each of the superior maxillary 

 bones is connected with its fellow, with the os 

 frontis, one os nasi, one lachrymal bone, the eth- 

 moid sphenoid, one os jugale, or cheek bone, one 

 palatine bone, and one inferior spongy bone, by 

 harmony, and by the vomer, and both by gom- 

 phosis, a species of union already explained. The 

 chief offices or uses of these bones, are to form 

 part of the face, palate, nose, nostrils, and orbits, 

 and to afford a convenient situation for the organ 

 of mastication. The processes and cavities of these 

 bones are numerous, but as no practical purpose 

 could be served by their enumeration, in a work 

 of this description, we do not attempt the task. 

 There are, however, usually eight alveolar cavities 

 in each bone, to receive the teeth, that is, in all 

 sixteen, in the upper jaw, which is formed of these 

 bones. There is also a cavity, the antrum maxil- 

 lare, called also the antrum Highmore, in the body 

 of the bone, between the orbital and palatine pro- 

 cesses, which has an opening into the nostrils, 

 and which is frequently the seat of disease, and 

 .therefore requires a more particular notice. An 

 abscess forms in this antrum of Highmore, (the 

 anatomist who first described it) ; and as it is ne- 

 cessary to perform an operation, to give exit to the 

 pus or matter, a trocar must be introduced, and it 

 the first of the molar teeth under the affected an- 

 trum be under its socket, the operation must be 

 varied. These bones are subject to caries, from 

 disease in the antrum, or cavity, and likewise 

 from polypus, and it is not an unfrequent occurrence 

 for nearly the whole bone to come away from the 

 venereal disease, and also from a long continued 

 salivation. In warm climates, flics have been 

 known to deposit their ova, or eggs, in the nose, 

 and in this antrum, where they soon become flies, 

 which irritate the lining membrane, and induce in- 

 flammation and abscess, which must be evacuated by 

 means of a trocar, or as a common abscess, from 

 any other cause. There are no less than ten muscles 

 attached to this bone, all connected with the face 

 and motions of the jaws and mouth, which need 

 not be enumerated by name. 



Ossa Palatina, or Palatine Bones, which, from 

 their situation, cannot be seen in the plate. Each of 

 these bones is united to its fellows, to the superior 

 maxillary bone, the sphenoid, ethmoid, inferior 

 spongy bone, and bones by harmony, and from the 

 posterior part of the palate, and part of the nose 

 and orbit. They are extremely irregular in their 



shape, and ascend laterally from the posterior part 

 of the nose to the orbits. This irregularity of 

 their figure, and their situation, has given rise to 

 their division into four portions, and they have also 

 the same number of processes, taking their names 

 from those of the portions, viz. the palatal, ptery- 

 goid, nasal, and orbitary. The palatine bones are 

 very perfectly formed at birth, and five muscles are 

 attached to, or connected with, these bones. The 

 palatine portions, or palatal plate, are extremely 

 subject to caries from syphilis, and those who can 

 afford it, have a substitute in the form of a gold 

 or silver palate. 



Vomer, The vomer, at birth, consists of two 

 distinct lamellae, with an intervening cartilage. 

 Superiorly, it is united with the sphenoid and the 

 ethmoid bones, interiorly with the superior maxil- 

 lary and palatine bones, and anteriorly to the car- 

 tilaginous septum of the nose ; its office being to 

 sustain and divide the cavity of the nostrils. It 

 bears some resemblance to the plough share of 

 former times ; and hence its name, which is derived 

 from vomo, to turn. It is, like its more immediate 

 neighbours, very liable to caries. 



Ossa Turbinata, or Turbinated bones, sometimes 

 called the inferior spongy bones, are each united 

 with the inferior maxillary ; the palate lachrymal 

 and ethmoid bone being situated in the side and 

 lower parts of the nostrils, are of 'a spiral and 

 convulated figure, and augment the surface of the 

 organ of smell. They are particularly subject not 

 only to caries, but to total destruction from syph- 

 ilis and nasal polypi. 



Os Maxillare Inferius, or Lower Jaw Bone 

 (No. 10. fig. 1.) The lower jaw bone is united to 

 the temporal bones by ginglymus, with the teeth by 

 gomphosis, and with the os byoides, or bone of the 

 tongue, and other parts, by syssarcosis, or by means 

 of muscle. It is shaped somewhat like a horse 

 shoe, and occupies the inferior and anterior part of 

 the face. It serves many very important purposes, 

 giving place to the roots of the teeth, in the 

 alveolar margin, constituting the inferior segment 

 of the cavity of the mouth, and affording a point 

 of adhesion to the muscles of the face, neck, larynx, 

 and tongue, there being not less than twelve pair 

 of muscles attached, both externally and internally, 

 while one passes over it. The most important of 

 these is the temporal muscle, which occupies the 

 whole temporal cavity, and terminates inferiorly in 

 a strong tendon, which is attached or inserted into 

 the coronoid, or crow's beak like process of the 

 inferior maxilla. Those who have a taste for 

 animal mechanics, will find their curiosity, labour, 

 and study, sufficiently rewarded by an attentive 

 inspection of the connections of this bone. The 

 ginglymus joint is formed by the large articular 

 cavity of the temporal bone, receiving the con- 

 dyloid, or rounded process of the lower jaw. In 

 this joint there is a movable inter articular carti- 

 lage, which is very closely connected to the con- 

 dyloid process, and the articular cavity by liga- 

 ments arising from their edges, and the whole is 

 surrounded by a capsular ligament, fixed to the 

 temporal bone and the neck of the condyle. The 

 peculiar formation of this joint gives to the lower 

 jaw many motions ; thus, when the condyles or 

 rounded ends slide forxvards, the lower jaw passes 

 horizontally forwards, as in the action of biting, 

 or the condyles only may be brought forwards while 

 the rest of the jaw passes backwards, as is the case 

 when the mouth -s open. The condyles may also 



