74 



A MANUAL OF ANATOMY 



has the shape of a four-sided pyramid, and presents four surfaces 

 (one of which is concealed by the tympanic plate), four borders, an 

 apex, and a base. The surfaces are superior, posterior, inferior, and 

 axxterior. 



The superior surface, which has an inclination forwards, looks into 

 the middle fossa of the base of the skull, and towards its outer part 

 presents a few digitate impressions for convolutions of the temporo- 

 sphenoidal lobe of the cerebrum. Near the apex is the Gasserian 

 depression for the Gasserian ganglion, and below this is the outlet of 



Superior Border of Squamous Portion 



Petro-squamous 



Groove or 



Suture- 



Zygoma ^ 



Eminentia Arcuata 



Sigmoid Groove for 

 Lateral Sinus 



Meningeal Groove 



Petro-squamous 



Angle 



Outlet of Carotid 

 Canal 



Mastoid Foramen 



/ 1 



Internal .-Vuditory Meatus ' ' 



I Aqueductus Cochlex 



Styloid Process 



Fig. 49. — The Right Temporal Bone (Internal View). 



the carotid canal for the internal carotid artery. Proceeding back- 

 wards and outwards, there is a small groove leading to a foramen 

 very nearly in line with the petro-squamous angle, called the hiatus 

 Fallopii, within the thin margin of which there may be two openings. 

 The inner and larger of these openings leads to the commencement 

 of the aqueduct oJ[ Fallopius, and thence to the internal auditory 

 meatus, and it transmits the great superficial petrosal nerve, along 

 with the petrosal branch of the middle meningeal artery. The 

 outer opening, of small size, also leads to the aqueduct of Fallopius, 



