THE MAXILLA 



101 



The Body (corpus maxillae}. The body is somewhat cuboid and is hollowed 

 out in its interior to form a large cavity, the antrum of Highmore (sinus maxillaris). 

 Its surfaces are four an external or facial, a posterior or zygomatic, a superior 

 or orbital, and an internal or nasal. 



Surfaces. The facial surface (fades anterior) (Fig. 7tt) is directed forward and 

 outward. It presents at its lower part a series of eminences corresponding to the 

 position of the anterior five teeth. Just above those for the incisor teeth is a 

 depression, the incisive fossa, which gives origin to the Depressor alae nasi; and 

 below it to the alveolar border is attached a slip of the Orbicularis oris. Above 

 and a little external to it the Compressor naris arises. More external is another 

 depression, the canine fossa (fossa canina), larger and deeper than the incisive fossa, 

 from which it is separated by a vertical ridge, the canine eminence, corresponding to 

 the socket of the canine tooth. The canine fossa gives origin to the Levator anguli 

 oris. Above the canine fossa is the infraorbital foramen (foramen infraorbitale), 



Outer Surface. 



TENDO OOUL 



Incisim fossa. 



Posterior dental 

 canals. 



Maxillary tuberosity. 



FIG. 70. Left maxilla. Outer surface. 



the termination of the infraorbital canal; it transmits the infraorbital vessels and 

 nerve. Sometimes the infraorbital canal opens by two, very rarely by three, 

 orifices on the face. Above the infraorbital foramen is the margin of the orbit 

 (margo infraorbitalis), which affords partial attachment to the Levator labii 

 superioris proprius. To the sharp margin of bone which bounds this surface in 

 front and separates it from the internal surface is attached the Dilator naris 

 posterior. 



The posterior (fades infratemporalis) or zygomatic surface is convex, directed 

 backward and outward, and forms part of the zygomatic fossa. It is sepa- 

 rated from the facial surface by a strong ridge of bone, the malar process, which 

 extends upward from the socket of the second molar tooth. It presents about 

 its centre several apertures leading to canals in the substance of the bone; 

 they are termed the posterior dental canals (foramina alveolaria^ and transmit 

 the posterior dental vessels and nerves. At the lower part of this surface is a 



