144 



OSTEOLOGY 





aquaeductus cochleae, which lodges a tubular prolongation of the dura mater establish- 

 ing a communication between the peril ymphatic space and the subarachnoid space, 

 and transmits a vein from the cochlea to join the internal jugular; (4) behind these 

 openings is a deep depression, the jugular fossa, of variable depth and size in different 

 skulls; it lodges the bulb of the internal jugular vein; (5) in the bony ridge dividing 

 the carotid canal from the jugular fossa is the small inferior tympanic canaliculus 

 for the passage of the tympanic branch of the glossopharyngeal nerve; (6) in the 

 lateral part of the jugular fossa is the mastoid canaliculus for the entrance of the 

 auricular branch of the vagus nerve; (7) behind the jugular fossa is a quadrilateral 

 area, the jugular surface, covered with cartilage in the fresh state, and articulating 

 with the jugular process of the occipital bone; (8) extending backward from the 

 carotid canal is the vaginal process, a sheath-like plate of bone, which divides 



Semicanals for 



auditory 



tube and 



Tensor 



tympani 



Stylopluiryngeus 



Lev. veli palatini 



Rough quadrilateral surface 



Opening of carotid canal 



Inferior tympanic canaliculus 



Aquceductus cochlea; 



Mastoid canaliculus 



Jugular fossa 



Vaginal process 



Styloid process 



Stylomastoid foramen 



Jugular surface 



Tympanomastoid fissure 



FIG. 141. Left temporal bone. Inferior surface. 



behind into two laminae; the lateral lamina is continuous with the tympanic part 

 of the bone, the medial with the lateral margin of the jugular surface; (9) between 

 these laminae is the styloid process, a sharp spine, about 2.5 cm. in length; (10) 

 between the styloid and mastoid processes is the Stylomastoid foramen; it is the 

 termination of the facial canal, and transmits the facial nerve and styTomastoid 

 artery; (11) situated between the tympanic portion and the mastoid process is the 

 tympanomastoid fissure, for the exit of the auricular branch of the vagus nerve. 

 Angles. The superior angle, the longest, is grooved for the superior petrosal 

 sinus, and gives attachment to the tentorium cerebelli; at its medial extremity 

 is a notch, in which the trigeminal nerve lies. The posterior angle is intermediate 

 in length between the superior and the anterior. Its medial half is marked by 

 a sulcus, which forms, with a corresponding sulcus on the occipital bone, the 

 channel for the inferior petrosal sinus. Its lateral half presents an excavation 

 the jugular fossa which, with the jugular notch on the occipital, forms the 



