THE BONES OF THE HEAD 



77 



the jugular fossa, is the opening of the tympanic canaliculus for the 

 tympanic branch (Jacobson's nerve) of the glosso-phar>'ngeal and 

 the tympanic branch of the ascending pharyngeal artery. Behind 

 the jugular fossa, internal to the stylo-mastoid foramen, is the 

 rough jugular facet for articulation with the extremity of the 

 jugular process of the occipital, by synchondrosis up to the 

 twenty-fifth year, after which ankylosis takes place. External 

 to the jugular facet is the styloid process, unmediately behmd 



Squamous Portion 



Zygoma — 



Surf, for Zygom. Fossa — 

 Eminentia Ardcularis ; - 



Ant. Part of Glen. Fossa 



Fissure of Glaser 



Post. Part of Glen. Fossa' 



Ext. \ud. Process 



Stylo-mastoid Foramen 



Mastoid Process , 



Digastric Groove 



Occipital Groove 



Orifice of Eustachian Canal 



Surface for Levator Palati 

 I 



Outlet of Carotid Canal 



I 



[ Apex of Petrous Portion 



'^>'' " Groove for Inf Petr. Sinus 

 Carotid Foramen 



Aqueductus Cochlea 



>r. for Ty 



jmpanic ( 



\ ^^ JuguUr Fossa 



N^ ^^ ^For. for Tymp. Sympath. Nerve 

 ■^ '^-Tvmpanic Canaliculus 



Auricular Canaliculus 

 Jugular Facet 



Styloid Process 



I Tympanic Plate 



Fig. 51. — The Right Temporal Bone (Inferior View). 



the root of which is the stylo-mastoid foramen. This foramen 

 is the outlet of the aqueduct of Fallopius, and by it the facial 

 nerve makes its exit, whilst the stylo-mastoid branch of the 

 posterior auricular artery passes in. A little behind the stylo- 

 mastoid foramen, between the mastoid process and tympanic 

 plate, is the auricular or tympano-mastoid fissure for the exit of 

 Arnold's nerve. 



The anterior or tympanic surface which is concealed by the 

 tympanic plate, looks into the tympanic cavity, of which it 



