SUPERIOR MAXILLARY BOXE. 



83 



which, is continuous, on the inner side, with the nasal, on the outer side, with the 

 malar process. Along the middle line of the orbital surface is a deep groove, the 

 infra-orbital, for the passage of the infra-orbital nerve and artery. This groove 

 commences at the middle of the outer border of this surface, and, passing forwards, 

 terminates in a canal which subdivides into two branches ; one of the canals, the 

 infra-orbital, opens just below the margin of the orbit ; the other, which is smaller, 

 runs in the substance of the anterior wall of the antrum ; it is called the anterior 

 dental canal, transmitting the anterior dental vessels and nerves to the front teeth 

 of the upper jaw. At the inner and fore part of the orbital surface, just external 

 to the lachrymal canal, is a minute depression, which gives origin to the Inferior 

 oblique muscle of the eye. 



The internal surface (fig. 46) is unequally divided into two parts by a horizontal 

 projection of bone, the palate process; that portion above the palate process forms 

 part of the outer wall of the nose; the portion below it forms part of the cavity 

 of the mouth. The superior division of this surface presents a large irregular 

 shaped opening leading into the antrum of Highmore. At the upper border of 



Fig. 46. Left Superior Maxillary Bone. Inner Surface. 



- partudZy eloei-ny Or, fee 

 mar/cfj ^n 



Ethmoid 



Infer {or Tur&imittct ^ 

 fuLutr 



Ant. Nasal S 



paused through 



this aperture are a number of broken cellular cavities, which, in the articulated 

 skull, are closed in by the ethmoid and lachrymal bones. Below the aperture is a 

 smooth concavity which forms part of the inferior ineatus of the nose, traversed 

 by a fissure, the maxillary fissure, which runs from the lower part of the orifice of 

 the antrum obliquely downwards and forwards, and receives the maxillary process 

 of the palate bone. Behind it is a rough surface which articulates with the per- 

 pendicular plate of the palate bone, traversed by a groove which, commencing near 

 the middle of the posterior border, runs obliquely downwards and forwards, and 

 forms, when completed by its articulation with the palate bone, the posterior palatine 

 canal. In front of the opening in the antrum is a deep groove, conyerted into a 

 canal by the lachrymal and inferior turbinated bones, and lodging the nasal duct. 

 More anteriorly is a well-marked rough ridge, the inferior turbinated crest, for 

 articulation with the inferior turbinated bone. The concavity above this ridge 

 forms part of the middle meatus of the nose ; whilst that 4 below it forms part of 

 the inferior meatus. The inferior division of this surface is concave, rough and 



