46 SUPERIOR 'MAXILLARY BONES. 



The body is triangular in form, and hollowed in its interior into 

 a large cavity, the antrum maxillare (antrum of Highrnore). It 

 presents for examination three sides ; an external or facial, internal 

 or nasal, and a posterior or zygomatic, and a superior surface the 

 orbital. The external or facial surface forms the anterior part of 

 the bone ; it is irregularly concave, and pre- 

 Fig. 19.* sents a deep depression towards its centre, 



the canine fossa, which gives attachment to 

 two muscles, the compressor nasi and levator 

 anguli oris. Immediately above this fossa 

 is the infra-orbital foramen, the termination 

 of the infra-orbital canal, transmitting the 

 superior maxillary nerve, and infra-orbital 

 artery ; and above the infra-orbital foramen, 

 the lower margin of the orbit, continuous 

 externally with the rough articular surface 

 of the malar process, and internally with a 

 thick ascending plate, the nasal process. 

 Towards the middle line of the face this 

 surface is bounded by the concave border 

 of the opening of the nose, which is projected forwards at its in- 

 ferior termination into a sharp process, forming, with a similar pro- 

 cess of the opposite bone, the nasal spine. Beneath the nasal spine, 

 and above the two superior incisor teeth, is a slight depression, the 

 incisive or myrtiformfossa, which gives origin to the depressor labii 

 superioris alreque nasi muscle. The myrtiform fossa is divided 

 from the canine fossa by a perpendicular ridge, corresponding with 

 the direction of the root of the canine tooth. The inferior boundary 

 of the facial surface is the alveolar process which contains the 

 teeth of the upper jaw, and it is separated from the zygomatic sur- 

 face by a strong projecting eminence, the malar process. The in- 

 ternal, or nasal surface, presents a large irregular opening, leading 

 into the antrum maxillare ; this opening is nearly closed in the ar- 

 ticulated skull by the ethmoid, palate, lachrymal, and inferior turbi- 

 nated bones. The cavity of the antrum is somewhat triangular, 

 corresponding in shape with the form of the body of the bone. 

 Upon its internal surface are numerous grooves, lodging branches 

 of the superior maxillary nerve, and projecting into its floor several 

 conical processes, corresponding with the roots of the first and 

 second molar teeth. In front of the opening of the antrum is the 



* The superior maxillary bones of the right side, as seen from the lateral aspect. 1. 

 The external, or facial surface ; the depression in which the figure is placed is the 

 canine fossa. 2. The posterior, or zygomatic surface. 3. The superior, or orbital sur- 

 face. 4. The infra-orbital foramen ; it is situated immediately below the number. 5. 

 The infra-orbital canal, leading to the infra-orbital foramen. 6. The inferior border of 

 the orbit. 7. The malar process. 8. The nasal process. 9. The concavity forming 

 the lateral boundary of the anterior nares. 10. The nasal spine. 11. The incisive, or 

 myrtiform fossa. 12. The alveolar process. 13. The internal border of the orbital 

 surface, which articulates with the ethmoid and palate bone. 14. The concavity which 

 articulates with the lachrymal bone, and forms the commencement of the nasal duct. 

 15. The palate process, i. The two incisor teeth, c. The canine. 6. The two bicus- 

 pidati. m. The three molares. 



