ANATOMY IN A NUTSHELL. 519 



auditorius interims. It transmits a small artery and vein and Lodges a process 

 of the dura mater. 



3. An angulah depression, which transmits a vein to the cancellous 

 tissue ami lodges a process of the dura mater, is between and above these other 

 openings. 



LESSON CLXXIV. 



The inferior surface of the petrous portion of the temporal hone forms pai I 

 of the hase of the skull and from its apex to its base it has the following points 

 for consideration: (Plate CCXLIX.) 



1. A rough quadrilateral surface for the origin of the Levator palati 

 and Tensor tympani muscles. 



2. Opening <>f the carotid canal which ascends vertically into the hone 

 and then turning runs horizontally forward and inward. It transmits the 

 interna] carotid artery and carotid plexus. 



3. Aqueductus cochleae, which transmits an artery and vein to and from 

 the cochlea. 



4. Jugular fossa is a depression for the sinus of the internal jugular vein, 

 and with the occipital hone forms the foramen lacerum posterius, which trans- 

 mits the internal jugular vein and the ninth, tenth, and eleventh cranial nerves. 



5. Foramen foe Jacobson's nerve (tympanic branch of the glossopharyn- 

 geal) is in the ridge between the jugular fossa and the carotid canal. 



6. Foramen for Arnold's nerve (auricular branch of the pneumogastric) 

 is in the outer wall of the jugular fossa. 



7. The jugular surface is a smooth quadrilateral facet which articulates 

 with the jugular process of the occipital bone. 



8. Vaginal process ensheaths the rool of the styloid process and gives 

 attachment to the Tensor palati muscle. 



!). Styloid prockss, which is about an inch long and runs downward, for- 

 ward, and inward, and gives attachment to the stylo-hyoid, stylo-maxillary 

 ligaments, and to the Stylo-pharyngeus, Stylo-hyoid, and Stylo-glossus muscles. 



10. STYLO-MASTOID FORAMEN is between the styloid process and the mas- 

 toid process. It is the end of the aqueductus Fallopii and transmits the facial 

 nerve, and the stylo-mastoid artery enters it. 



11. THE AURICULAE FISSURE, which is between the auditory and mastoid 



processes, is for the exit of Arnold's nerve. 



Till-: SUPERIOR BORDER of the pet nuts portion of the temporal hone i> the 



longest and is grooved for the superior longitudinal sinus. It gives attachment 

 to the tentorium cerebelli and has a notch :it its inner end lor the fifth nerve. 

 It separates the middle fossa of the base of the skull from the posterior fossa. 



The posterior border of the petrous portion of the temporal bone has on 

 its inner half a groove, which with n similar groove on the occipital bone l< 

 ihe inferior petrosal sinus. On the outer half of this border is ;i notch which 

 forms part of the jugular foramen. 



Tut': anterior border of the petrous portion of the temporal bone is the 



