OSSA TEMPORUM. 69 



There is another small oblique foramen immediately beneath 



this, which transmits the nervous peirosus superficialis minor, a 

 branch of Jacobson's nerve ; near the apex of the petrous por- 

 tion of the temporal bone there is seen a large foramen, the 

 termination of the carotid canal. On this anterior face of the 

 bone, especially in the young subject, is seen a rising or eminence 

 running from base to apex, which is formed by the projection 

 of the perpendicular semicircular canal. 



About the middle of the posterior side is the large aperture 

 called meatus auditorius internus. The bottom of this cavity 

 is perforated by several foramina : the largest and uppermost 

 of which is the orifice of a winding canal, called improperly 

 the aqueduct of Fallopius, which transmits the portio dura of 

 the seventh pair of nerves. The other foramina transmit the 

 fibres of the portio mollis of the same nerve. Posterior to the 

 orifice of the meatus internus is an oblong depression, with a 

 foramen in it, covered by a shell of bone, which is the orifice 

 of a proper aqueduct or canal that passes from the vestibule of 

 the ear.* 



— Neither of the so called aqueducts of the vestibule or cochlea, 

 are deserving of the name which has nevertheless been con- 

 tinued to designate them, since we no longer believe with 

 Cotugnius their discoverer, that they are a sort of passages, to 

 admit of the overflow of the lymph, when it was secreted in 

 superabundance in the labyrynth. They are both mere open- 

 ings, for the transmission mainly of blood vessels. The aque- 

 duct of the vestibule transmits a small artery and vein to the 

 vestibule, and lodges a process of the dura mater. — 



The inferior side of the petrous portion forms a part of the 

 external surface of the basis of the cranium. On the back part 

 of it is the external orifice of the canal, through which the 

 portio dura passes. It is called foramen stylo mastoideum. 

 Before this foramen is a long and slender styloid process, 

 which varies from one to two inches in length ; it projects 



* This orifice should not be confounded with one which is nearer to the meatus 

 internus, and situated on the angle made by the two sides of the bone. — h. 



