2IO 



HUMAN ANATOMY. 



lates with the front of the malar process of the maxilla, bounding externally the 

 rough surface of the inner side of the malar. The antero-superior, or orbital border, 

 is smooth and concave, forming the external and most of the inferior boundary of 

 the orbit. The orbital plate, or process, which forms the front of the outer wall of 

 the orbit, projects inward from this border, joining the bone at nearly a right angle. 



Fig. 239. 



Malar canal 



Tuberosity 

 Right malar bone, outer aspect. 



It is narrow in front and broad behind, where its anterior surface looks towards the 

 orbit and its posterior towards the temporal fossa. Its projecting edge is jagged 

 throughout, and in front meets the superior maxilla. Behind that it joins the outer 

 border of the great wing of the sphenoid, and above articulates with the frontal. Be- 

 tween the part meeting the maxilla and that meeting the great wing there is usually a 



short, smooth surface bound- 



FiG. 240. 



^ Frontal process 



Temporal canal 



Malar canal 



Orbital process 



Teniporo-zygo- 

 matic surface 



ing the end of the spheno- 

 maxillary fissure, which lies 

 between* these bones in the 

 lower outer angle of the orbit. 

 Two foramina on the orbital 

 surface lead to minute canals. 

 The lower, the malar, ^ opens 

 on the outer surface of the 

 bone ; the upper, the tem- 

 poral,'^ opens on the back of 

 the orbital process. They 

 transmit branches from the 

 superior maxillary division of 

 the fifth nerve. They vary 

 greatly. 



In all mammals the pri- 

 mary function of the malar is 

 to unite the maxilla and the 

 temporal bone. Its union 

 with the frontal is a further development. Only in primates does it join the sphe- 

 noid and separate the orbit from the temporal fossa. 



Articulations, — The malar bone articulates with the frontal, superior maxillary, 

 temporal, and sphenoid bones. 



Development and Variations. — There are three centres of ossification — an 



' Foramen zygomaticofaciale. " Foramen zygomaticotemporale. 



Maxillary surface 



Right malar bone, inner aspect. 



