BONES OF THE SKULL. 



THE CRANIUM As A WHOLE. 



Anterior Aspect (norma frontalis). This includes the fron- 

 tal, malar, nasal, and superior maxillary bones; it presents the 

 orbital fossae, one lying on each side, with the orifice of the nasal 

 fossa between and below them. [148] 



Frontal Region. This is convex and limited laterally by 

 two ridges (temporal lines) ; it is formed by the frontal bone, 

 which presents inferiorly the arched upper (orbital) margins 

 of the orbits. Each orbital margin presents a (supra-orbital) 

 notch, or foramen, near its inner third; externally it is thin 

 and sharp and ends in a (external angular) process which joins 

 a (frontal) process of the malar; internally it is rounded and 

 ends in another (internal angular) process which joins a (fron- 

 tal) process of the superior maxilla. The space between the in- 

 ternal angular processes is the root of the nose and may pre- 

 sent the remains of a mesial suture between the original halves 

 of the frontal. It also presents, just above the naso-f rental 

 suture, a median prominence (glabella) from which a (supra- 

 orbital) ridge runs outward on each side above the orbit; 

 above each ridge is a fulness (frontal eminence). [148] 



Orbital Fossa. This is a four-sided pyramid whose base is 

 the orbital aperture; its apex is directed backward and in- 

 ward, so that the axes of both fossae converge behind. The 

 margin of the aperture is formed above by the orbital margin 

 of the frontal ; in the outer, and half the lower, part by the 

 sharp (orbital) margin of the malar; and in the inner, and half 

 the lower, part by the frontal process and sharp (orbital) mar- 

 gin of the body of the superior maxilla. A narrow cleft (sphe- 

 noidal fissure) runs outward and slightly upward, from the 

 apex, between the wings of the sphenoid ; above and internal 

 to its inner end is a small (optic foramen) opening between 

 the roots of the lesser wing of the sphenoid. [148] 



The roof is concave and formed in front by the orbital plate 

 of the frontal, and behind by the lesser wing of the sphenoid. 



[5] 



