FEONTAL BONE. 



3-5 



lono'itudinal sinus ; and a depression at the posterior inferior angle 

 forms a small part of the groove of the lateral sinus. Near the upper 



Fig. 30.— The Parietal Bone Fig. 30. 



FROM THE Inside. (A.T.) ^ 



1, 2, 3, 4, 6, & 8, iudicate 

 the same i^arts as in the 

 last figure : between 1 & 2 

 the half groove of the su- 

 perior longitudinal sinus ; 3', 

 groove of the lateral sinus ; 

 7, the ramified grooves of the 

 meningeal vessels ; above x 

 this groove is converted into a 

 canal ; 9, the irregular pits 

 for the glaudulos Pacchionii. 



border there are in most 

 skulls, but particularly 

 in those of old persons, 

 small irregular pits, 

 fovecc glandulares, lodg- 

 ing the so-named gland- 

 ular Pacchionii. 



Borders. — The ante- 

 rior, superior, and ])os- 

 terior borders are deeply serrated 



the greater part of its extent a sharp or squamous edge, with a slightly 

 fluted surface directed outwards and overlapped at its anterior extremity 

 by the great wing of the sphenoid, and beliind that by the squamous 

 part of the temporal bone ; its posterior part is serrated, and articu- 

 lates with the mastoid portion of the temporal. The anterior border 

 is slightly overlapped by the frontal bone above, but overlaps the 

 edge of that bone inferiorly. 



The inferior border presents iu 



THE FRONTAL BONE 



The frontal bone, arching upwards and backwards from above the 



orbits, forms the fore part of the cranium. It likewise presents 

 inferiorly two thin horizontal laminte, the orbiial plates, which form 

 the roofs of the or])its and are separated by a mesial excavation, the 

 incisura efhmoidaJis. 



The frontal is articulated with twelve bones, viz., posteriorly with 

 the parietals and sphenoid ; outside the orbits with the malars ; and 

 between the orbits, from before backwards, with tiie nasal, superior 

 maxillary, lachrymal, and ethmoid bones. 



Anterior surface. — The part forming the greatest convexity of the 

 foreliead on each side is called the froifal eminence. It is separated by 

 a slight depression below from the superciUary ridge, a curved elevation 

 of varying prominence immediately above the margin of the orbit. 

 Between the superciliary ridges is the surface called filahella. The 

 margin of the orbit, the orbital arch, is most defined towards its outer 

 part ; it presents towards its inner third the supraorhital notch, some- 

 times converted into a foramen, which transmits the supraorI)ital nerve 

 and artery. The extremities of the orbital arch point downwards, and 



