THE SKULL THE CKANIUM 285 



above by the gently convex horizontal surface. The lower border 

 begins behind at the posterior middle angle, curves downward, and, 

 following the concavity of the upper part of the cerebral surface, 

 becomes slightly convex where it joins the mesethmoid. The anterior 

 border is emarginate. 



Nomenclature. Frontal is fromfrons, the forehead. Osfrontale 

 and os frontis are the Latin anatomical terms most generally used. The 

 French is le frontal, and the German equivalent das Stirnbein. Old 

 names are os coronale, the bone which bore the crown, os sincipitis, the 

 bone of the sinciput, or forepart of the head, and os prorce, the prow 

 bone, from the resemblance of the anterior end of the inverted cal- 

 varium to the prow of a ship. 



Determination. When the frontal is held with the external 

 flattened surface uppermost and the broader posterior end toward 

 the student, the postorbital process is on the side to which the bone 

 belongs. 



Articulation. The frontal articulates with the nasal, the maxil- 

 lary, the lachrymal, the ethmoid, the palatine, the orbitosphenoid, the 

 alisphenoid, the parietal, and the opposite frontal. 



Muscular Attachments. The temporal is attached to the outer 

 surface of the horizontal and vertical plates below the temporal line 

 and to the posterior surface of the postorbital process. To the orbital 

 rini is fastened a strong fascia, in which are inserted parts of the 

 occipito-frontalis and the orbicularis palpebrarum. 



VARIATIONS IN THE FRONTAL BONES. 

 VARIATIONS IN SIZE. 



The following measurements were taken upon a large number of 

 frontal bones ; when several specimens were identical in size only one 

 was noted in the table. 



The maximum length is the length along the metopic suture from 

 the posterior angle of the horizontal plate to the tip of the nasal spine. 



The maximum width is the distance from the most convex part of 

 the temporal surface to the plane of the medial surface of the median 

 plate. 



The maximum height is the distance, taken at a right angle, from 

 the superior surface of the horizontal plate to the lowest point of the 

 vertical plate. 



