THE FRONTAL BONE. 



13 



there are some sharp, pit-like depressions which lodge the 

 Pacchionian glands, small fibrous bodies developed on 

 the outer surface of the dura mater. Running along the 

 middle line from the superior border to a pit in front of 

 the ethmoidal notch is the frontal crest, which gives attach- 

 ment to the falx cerebri and lodges the longitudinal sinus. 

 The horizontal portion consists of two orbital plates, 

 separated by a deep, broad notch, the ethmoidal. These 

 plates present for examination inferior and superior sur- 



Frontal Si nut 



\ Krpa nJtJ l*M ff b'aial Spmf, 

 JTH*I*J f*-t <f R,,f f tfau 



FIG. 3. FRONTAL BONE, INNER SURFACE. 



faces, posterior and ethmoidal borders. The inferior sur- 

 face is strongly concave and smooth, the superior slightly 

 convex and marked by the convolutions of the brain. 

 Just within the external angular process is a shallow de- 

 pression which lodges the lachrymal gland. Behind the 

 internal angular process is a small tubercle, sometimes a 

 depression which gives attachment to the pulley of the 

 superior oblique muscle. The orbital plates are thin 

 and translucent, consisting of compact tissue only. The 

 posterior border articulates with the lesser wing of the 



