PALATE BONES. 47 



ia concave and rises towards the middle line, where it unites with its 

 fellow of the opposite side and forms part of a crest (crista nasalis), 

 which articulates with the vomer. The inferior surface is uneven, 

 and marked by a slight transverse ridge, to which is attached the 

 tendinous expansion of the tensor palati muscle. Near to its 

 external border are two openings, one large and one small, the 

 posterior palatine foramina ; the former transmits the posterior pala- 

 tine nerve and artery, and the latter the middle palatine nerve. The 

 posterior border is concave, and presents at its inner extremity a 

 sharp point, which with a corresponding point in the opposite bone 

 constitutes the palate spine for the attachment of the azygos uvulae 

 muscle. 



The perpendicular plate is also quadrilateral ; and presents two sur- 

 faces, one internal or nasal, forming a part of the wall of the nares ; 

 the other external, bounding the spheno-maxillary fossa and antrum. 

 The internal surface is marked near its middle by a horizontal ridge 

 (crista turbinalis inferior), to which is united the inferior turbinated 

 bone, and at about half an inch above this by another ridge (crista 

 turbinalis superior) for the attachment of the middle turbinated bone. 

 The concave surface below the inferior ridge is the lateral boundary 

 of the inferior meatus of the nose ; that between the two ridges corre- 

 sponds with the middle meatus, and the surface above the superior 

 ridge with the superior meatus. The external surface, extremely irre- 

 gular, is rough on each side for articulation with neighbouring bones, 

 and smooth in the middle to constitute the inner boundary of the 

 spheno-maxillary fossa. This smooth surface terminates inferiorly in 

 a deep groove, which being completed by the tuberosity of the su- 

 perior maxillary bone and pterygoid process of the sphenoid, forms 

 the posterior palatine canal. 



Near the upper part of the perpendicular plate is a large oval notch 

 completed by the sphenoid, the spheno-palatine foramen, which trans- 

 mits the spheno-palatine nerves and artery, and serves to divide the 

 upper extremity of the bone into two portions, an anterior or orbital, 

 and a posterior or sphenoidal portion. The orbital portion is hollow 

 within, and presents five surfaces externally ; three articular, and two 

 free ; the three articular are the anterior, which looks forward and 

 articulates with the superior maxillary bone, internal with the ethmoid, 

 and posterior with the sphenoid. The free surfaces are the superior 

 or orbital, which forms the posterior part of the floor of the orbit, and 



forms the crista nasalis for the reception of the vomer. 5. The pointed pro- 

 cess, which with a similar process of the opposite bone forms the palate spine. 

 6. The horizontal ridge which gives attachment to the inferior turbinated bone ; 

 the concavity below this ridge enters into the formation of the inferior meatus, 

 and the concavity (2) above the ridge into that of the middle meatus. 7- The 

 spheno-palatine notch. 8. The orbital portion, p. The crista turbinalis supe- 

 rior for the middle turbinated bone. 10. The middle facet of the tuberosity, 

 which enters into the formation of the pterygoid fossa. The facets 1 1 and 3 

 articulate with the two pterygoid plates, 1 1 with the internal, and 3 with the 

 external. 



