THE TEMPORAL FOSSA. 



215 



the superior curved line of the occiput : and the sides by two lines, the one drawn 

 downward and backward from the external angular process of the frontal bone 

 to the angle of the lower jaw, the other from the angle of the jaw upward and 



O c( 



d V 



FIG. 174. Side view of the skull. 



backward to the outer extremity of the superior curved line. This region is 

 divisible into three portions temporal fossa, mastoid portion, and zygomatic fossa. 



The Temporal Fossa. 



The Temporal Fossa is bounded above and behind by the temporal ridge, which 

 extends from the external angular process of the frontal upward and backward 

 across the frontal and parietal bones, curving downward behind to terminate in 

 the posterior root of the zygomatic process. This ridge is generally double at all 

 events in front, where it is most marked. In front it is bounded by the frontal, 

 malar, and great wing of the sphenoid : externally by the zygomatic arch formed 

 conjoin tlv by the malar and temporal bones; below it is separated from the 

 made fossa by the pterygoid ridge, seen on the outer surface of the great 

 wing of the sphenoid. This fossa is formed by five bones, part of the frontal, 

 great wing of the sphenoid, parietal, squamous portion of the temporal, and malar 

 bones, and is traversed by six sutures, part of the transverse facial, spheno- 

 malpa\ coronal, spheno-parietal. squamo-parietal. and squamo-sphenoidal. The 

 point where the coronal suture crosses the temporal ridge is sometimes named 

 the gtephanion : and the region where the four bones, the parietal, the frontal, the 

 s<iuamous. and the gi-eater wing of the sphenoid, meet, at the anterior inferior angle 

 of the parietal bone, is named the pterion. This point is about on a level with the 



