to PALATE BONES. 



concave, partly smooth and partly rough ; smooth where it forms part of 

 the temporal fossa, and rough where it articulates with the superior maxil- 

 lary bone. 



The frontal process ascends perpendicularly to form the outer border 

 of the orbit, and to articulate with the external angular process of the 

 frontal bone. The orbital process is a thick plate, which projects inwards 

 from the frontal process, and unites with the great ala of the sphenoid to 

 constitute the outer wall of the orbit. It is pierced by several small fora- 

 mina, for the passage of the temporo-malar filaments of the superior 

 maxillary nerve. The maxillary process is broad, and articulates with 

 the superior maxillary bone. The zygomatic process, narrower than the 

 rest, projects backwards to unite with the zygoma of the temporal bnne. 



Development. By a single centre ; in rare instances, by two or three. 

 In many animals the malar bone is permanently divided into two portions, 

 orbital and malar. Ossification commences in the malar bone soon after 

 the vertebrae. 



Articulations. With four bones: three of the cranium, frontal, tem- 

 poral, and sphenoid ; and one of the face, the superior maxillary bone. 



Attachment of Muscles. To Jive: levator labii superioris proprius, 

 zygomaticus minor and major, masseter, and temporal. 



PALATE BONES. The palate bones are situated at the posterior part of 

 the nares, where they enter into the formation of the palate, the side of the 

 nose, and the posterior part of the floor of the orbit ; 

 hence they might, with great propriety, be named the 

 palato-naso-orbital bones. Each bone resembles, ip 

 general form, the letter L, and is divisible into a 

 horizontal plate, a perpendicular plate, and a ptery- 

 goid process or tuberosity. 



The horizontal plate is quadrilateral ; and presents 

 two surfaces, one superior, which enters into the for- 

 mation of the floor of the nares, the other inferior, 

 forming the posterior part of the hard palate. The 

 superior surface is 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), w r hich 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 ten- 

 sor palati muscle. Near its external border are two openings, one large 

 and one small, the posterior palatine foramina ; the former transmits the 



* A posterior view of the right palate bone in its natural position; it is slightly turned 

 on one side, to obtain a sight of the internal surface of the perpendicular plate (2). 1. The 

 horizontal plate of the bone; its upper or nasal surface. 2. The perpendicular plate; 

 its internal or nasal surface. 3, 10, 11. The pterygoid process or tuberosity. 4. The 

 thick internal border of the horizontal plate, which, articulating with the similar border 

 of the opposite bone, forms the crista nasalis for the reception of the vomer. 5. The 

 pointed process, which, with a similar process of the opposite bone, forms the palate 

 spine. 0. 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. 9. The crista turbinalis superior for the middle turbi- 

 nated bone. 10. The middle facet of the tuberosity, which enters into the formation of 

 the pterygoid fossa. The facets 11 and 3 articulate with the two pterygoid plates, 11 

 with the internal, and 3 with the external. 



