166 



OSTEOLOGY 





part is generally seen; this forms the anterior boundary of the inferior orbital fissure: 

 occasionally, this non-articular part is absent, the fissure then being completed 

 by the junction of the maxilla and sphenoid, or by the interposition of a small 

 sutural bone in the angular interval between them. The maxillary process presents 

 a rough, triangular surface which articulates with the maxilla. The temporal 

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

 temporal. 



Borders. The antero-superior or orbital border is smooth, concave, and forms 

 a considerable part of the circumference of the orbit. The antero-inferior or maxil- 

 lary border is rough, and bevelled at the expense of its inner table, to articulate 

 with the maxilla; near the orbital margin it gives origin to the Quadratus labii 

 superioris. The postero-superior or temporal border, curved like an italic letter /, 

 is continuous above with the commencement of the temporal line, and below with 

 the upper border of the zygomatic arch; the temporal fascia is attached to it. 

 The postero-inferior or zygomatic border affords attachment by its rough edge to 

 the Masseter. 



Ossification. The zygomatic bone is generally described as ossifying from three centers 

 one for the malar and two for the orbital portion; these appear about the eighth week and fuse 

 about the fifth month of fetal life. Mall describes it as being ossified from one center which 

 appears just beneath and to the lateral side of the orbit. After birth, the bone is sometimes 

 divided by a horizontal suture into an upper larger, and a lower smaller division. In some quad- 

 rumana the zygomatic bone consists of two parts, an orbital and a malar. 



Articulations. The zygomatic articulates with four bones: the frontal, sphenoidal, temporal, 

 and maxilla. 



Groove for 

 nasolacrimal duct 



Frontal process 



Maxillary sinus 

 Orbital process 



Sphenopalatine 

 notch 



Sphenoidal 

 process 



Conc'tial crest 



Conchal crest 



FIG. 167. Articulation of left palatine bone with maxilla. 



The Palatine Bone (Os Palatinum; Palate Bone). 



The palatine bone is situated at the back part of the nasal cavity between the 

 maxilla and the pterygoid process of the sphenoid (Fig. 167). It contributes 

 to the walls of three cavities: the floor and lateral wall of the nasal cavity, the 

 roof of the mouth, and the floor of the orbit; it enters into the formation of two 

 fossae, the pterygopalatine and pterygoid fossae; and one fissure, the inferior orbital 

 fissure. The palatine bone somewhat resembles the letter L, and consists of a 

 horizontal and a vertical part and three outstanding processes viz., the pyramidal 



