OSTEOLOGY AND SYNDESMOLOGY. 17 



This plate is perforated by numerous lioles, through which pass the ramifi- 

 cations of the olfactory nerve. The lateral portions of the ethmoid (j^l. 121, 

 ßg. 10 ^) are covered by the frontal bone. That portion of the ethmoid 

 which enters into the orbitar cavity [ßg. 14') is called the os planum, or 

 lamina papyracea. The internal or nasal face forms part of the nostril. 

 Between the two halves of the bone, and beneath the cribriform plate, is 

 the nasal lamella, or lamina perpendicidaris {ßg. 11', 12*, 13*), which, in 

 conjunction with the vomer, divides the nasal cavity into halves. In the 

 posterior middle portion of the nasal face is a deep furrow, called the supe- 

 rior nasal meatus {ßg. 15 *). The upper margin of this meatus is constituted 

 by the upper turbinated bone, the middle turbinated bone being below. 



B. Bones of the Face. 



The fece is composed of fourteen bones, of which thirteen enter into the 

 composition of the upper jaw. Of these, twelve are in pairs : the ossa max- 

 illaria superiora, ossa malarum, ossa nasi, ossa ungues, ossa turbinata inferi- 

 ora, ossa palati. The single vomer constitutes the thirteenth, and the os 

 maxillare inferius, or lower jaw, the fourteenth. 



Superior maxillary bones, ossa maxillaria superiora {pi. 121, ßgs. 1 '", 4 '" ; 

 pi. 123, ßg. 6). These are the largest of the bones of the face, and occupy 

 the anterior part of the upper jaw. Each consists of a central portion, 

 with various processes for articulation with the contiguous bones. This 

 central portion is hollowed out into a large cavity, called the antrum high- 

 mo7'iamim, or maxillary sinus, communicating with the cavity of the nose. 

 The superior face is formed by a thin plate, the orbitar process, constituting 

 the floor of the orbit {p)l. 128, ßg. 6 ^). In the posterior part of this plate is 

 a groove, which leads to a canal terminating at the front of the bone in the 

 infra-orbitar foramen {ßg. 6*- pi. 121, ßg. 4'), through which pass the 

 infra-orbitar nerve and an artery ; below tliis, again, is a depression in the 

 front of the bone {pi. 123, ßg. 6 °), known as the fossa maxillaris, filled up 

 during life by muscle and fat. The nasal process {ßg. 6''*) connects the 

 bone with the frontal and nasal bones, and exhibits an emargination inferiorly 

 and anteriorly {fi/j. 6 "), to which is attached the cartilage of the nose. The 

 malar or zygomatic process {ßg. 6 ') connects it with the malar bone. The 

 alveolar processes, for lodging the eight teeth of the adult, are situated in the 

 external inferior portion, and the palatine process (j)Z. 121, ßg. 6'°) consti- 

 tutes the greater portion of the bony palate. In the suture of the two max- 

 illary bones, and immediately behind the front alveolar processes, we find 

 the foramen incisivum {ßg. 6 '^), which bifurcates above, sending a branch 

 into each nostril. Through this passes a branch of the spheno-palatine 

 nerve. The intermaxillary bone, so universal in the lower Mammalia, is 

 wanting as a distinct clement in the adult man (it being fused with the true 

 maxillary), but in the young foetus may be distinctly recognised ; it rarely 

 exists after birth. The articulations of the maxillary bones are with the 

 frontal, nasal, unguiform, malar, and ethmoid, above ; with the palatine, 

 behind ; with the vomer, in the middle ; and with the inferior spongy bone, 

 by the nasal surface. 



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