88 



THE SKELETON 



into a canal by the lacrimal and inferior nasal concha and transmits the naso- 

 lacrimal duct. 



In front of the groove is a smooth surface crossed obliquely by a ridge, the conchal crest, 

 for articulation with the inferior nasal concha. The surface below the crest is smooth, concave, 

 and belongs to the inferior meatus; the surface above the crest extends on to the lower part of 

 the frontal process and forms the wall of the atrium of the middle meatus. Behind the open- 

 ing of the antrum the surface is rough for articulation with the vertical plate of the palate 

 bone, and crossing it obhquely is a smooth groove converted by the palate into the pterygo- 

 palatine canal for the passage of the (descending) palatine nerves and the descending palatine 

 artery. 



Fig. 109. — The Left Maxilla. (Outer view.) 



Infra-orbital foramen 



Nasal notch 



Canine fossa 



Anterior nasal spine 



Incisive fossa 



Canine eminence 



_ Border of inferior orbitalfissure 

 For sphenoid 

 Zygomatic surface 



Zygomatic process 



1 |fc==- Posterior alveolar canals 



— ^Tuberosity 



The frontal process, somewhat triangular in shape, rises vertically from the 

 angle of the maxilla. Its lateral surface is continuous with the anterior surface 

 of the body, and gives attachment to the orbicularis oculi, the medial palpebral 

 ligament and the quadratus lahii superioris {caput angular e). The medial sur- 

 face forms part of the lateral boundary of the nasal fossa and is crossed obliquely 

 by a low ridge, known as the agger nasi, limiting the atrium of the middle meatus. 



The hinder part of this surface rests on the anterior extremity of the labyrinth of the eth- 

 moid and completes the maxillo-ethmoidal cells. The superior border articulates with the 

 frontal; the anterior border articulates with the nasal bone; the posterior border is thick and 

 vertically grooved, in continuation with the lacrimal groove, and lodges the lacrimal sac. 

 The medial margin of the groove articulates with the lacrimal bone, and the junction of its 

 lateral margin with the orbital surface is indicated by the lacrimal tubercle. 



Fig. 110. — The Left Maxilla. (Inner view.) 



Frontal process 



Ridge for middle concha of ethmoid 



Lacrimal groove 

 Conchal crest 



Anterior nasal spine 

 Crest 



Incisive groove (canal) 



Sinus maxillaris 



Posterior palatine groove 

 Palatine process 



The zygomatic process, rough and triangular, forms the summit of tlie 

 prominent ridge; of boiu; separating the anterior and infratemporal surfaces. It 

 articuhites above with the zygomatic, and from its inferior angle a few fibres of 

 the masseter take origin. The anterior and posterior surfaces are continuous 

 with the anterior and infratemporal surfaces of the body. 



The palatine process projects horizontally from the medial surface and, with 

 the corresponcHng process of the opposite side, forms about three-fourths of the 

 hard palate. The superior surface is smooth, concave from side to side, and 



