THE PALATE BOXES. 197 



Worinian bone in the angular interval between them. On the upper surface of 

 the orbital process are seen the orifices of one or two temporo-malar canals ; one 

 of these usually opens on the posterior surface, the other (occasionally two) on 

 the facial surface : they transmit filaments (temporo-maler) of the orbital branch 

 of the superior maxillary nerve. The maxillary process is a rough, triangular 

 surface which articulates with the superior maxillary bone. The zygomatic pro- 

 is, long, narrow, and serrated, articulates with the zygomatic process of the 

 temporal bone. Of the four borders, the antero-superior or orbital is smooth, 

 arched and forms a considerable part -of the circumference of the orbit. The 

 anter<i-iiiT\-i-ior or maxillary border is rough, and bevelled at the expense of its 

 inner table, to articulate with the superior maxillary bone; affording attachment 

 by its margin to the Levator labii superioris proprius, just at its point of junction 

 with the superior maxillary. The postero-superior or temporal border, curved like 

 an italic letter f. is continuous above with the commencement of the temporal 

 ridge : below, with the upper border of the zygomatic arch : it affords attachment 

 to the temporal fascia. The posters-inferior or zygomatic border is continuous 

 with the lower border of the zygomatic arch, affording attachment by its rough 

 edge to the Masseter muscle. 



Development. The malar bone ossifies generally from two. but occasionally 

 from three, centres. One. which forms the chief part of the bone, appears about 

 the seventh week, near the orbital margin. The second appears somewhat later, 

 along the lower margin. The third, when it exists, is found in the hinder border. 

 The bone is sometimes, after birth, seen to be divided by a horizontal suture into 

 an upper and larger division and a lower and smaller. This divided condition is 

 probably due to the persistent separation of the two centres of ossification. In 

 some quadrumana the malar bone consists of two farts, an orbital and a malar, 

 which are ossified by separate centres. 



Articulations. With four bones : three of the cranium, frontal, sphenoid, and 

 temporal : and one of the face, the superior maxillary. 



Attachment of Muscles. To five : The Levator labii superioris proprius, 

 Zygomaticus major and minor, Masseter, and Temporal. 



The Palate Bones. 



The Palate Bones (palatnm, the palate) are situated at the back part of the 

 nasal fossae : they are wedged in between the superior maxillary bones and the 

 pterygoid processes of the sphenoid. Each bone assists in the formation of three 

 cavities : the floor and outer wall of the nose, the roof of the mouth, and the floor 

 of the orbit, and enters into the formation of two fossae, the spheno-maxillary and 

 pterygoid : and one fissure, the spheno-maxillary. In form the palate bone some- 

 what resembles the letter L, and may be divided into an inferior or horizontal 

 plate and a superior or vertical plate. 



The Horizontal Plate is thick, of a quadrilateral form, and presents two sur- 

 faces and four borders. The siit>erior surface, concave from side to side, forms 

 the back part of the floor of the nostril. The inferior surface, slightly concave 

 anu rough, forms the back part of the hard palate. At its posterior part may be 

 seen a transverse ridge, more or less marked, for the attachment of part of the 

 apMneurosis of the Tensor palati muscle. At the outer extremity of this ridge is 

 a deep groove converted into a canal by its articulation with the tuberosity of the 

 superior maxillary bone, and forming the posterior palatine canal. Near this 

 groove the orifices of one or two small canals, accessory posterior palatine, may be 

 seen. The anterior border is serrated, bevelled at the expense of its inferior sur- 

 face, and articulates with the palate process of the superior maxillary bone. The 

 rior border is concave, free, and serves for the attachment of the soft palate. 

 Its inner extremity is sharp and pointed, and. when united with the opposite bone, 

 forms a projecting process, the posterior nasal spine, for the attachment of the 

 Azygos uvulae. The external border is united with the lower part of the per} en- 



