THE SKULL THE CEANIUM 



191 



the zygomatic process, and longer and flatter at the upper border. 

 From above downward, for the anterior third, the surface is also convex, 

 more strongly in front of the zygomatic process ; for the middle third, 

 convex above and concave below ; and for the posterior third, concave. 

 In well-marked skulls a temporal ridge near the upper border, and 

 parallel with it, marks the upper limit of the attachment of the fibres 

 of the temporal muscle. The concavity above the posterior root of 

 the zygomatic process is continued forward on the upper surface of the 

 zygomatic process itself. It lies, for the most part, over the under 

 surface of that root, a surface classed as part of the inferior surface 

 of the squamous ; but the part nearest the middle line of the skull is 



FIG. 129. 



With Parietal. 



Glaserian Fissure. 



I 



Zygomatic Process. 



\ 



With Malar. 



Gtenoid Cavity, with Jaw. 



Postglenoid Foramen. 



Notch for Canal of Huguier. 

 Postglenoid Process. 



Groove for Eustachian Tube. 



With Basisphenoid. 



Posterior Root of Zygoma. 

 On Roof of Tympanum. 



Fenestra Oc"'/x. 



Fenestra Rotunda seen through aperture 

 of communication between Ecto- and 

 Entotympanic Chambers of Bulla. 



Stylo-mastoid Foramen. 



Mnxfoiii Process. 

 With Occipital. 



Pit for Tympano-hyal. 



Entotympanic part of Bulla. 



Ectotympanic part oj Bulla. 



LEFT TEMPORAL BONE, OUTER SURFACE. 



thin and enters into the formation of the roof of the tympanum, 

 forming more especially the roof of the deep fossa for the heads of 

 the two ossicles of the ear known as the malleus and incus. Occasion- 

 ally a small foramen is visible at the bottom of this concavity, but, as 

 a rule, the external surface of the squamous is free from foramina. 



The zygomatic process springs from the anterior lower angle of 

 the external surface. Its heavy, basal portion is directed almost 

 straight outward and slightly upward. It then narrows, turns sharply 

 forward, and arches upward, forward, and inward to overlap the zygo- 

 matic process of the malar. It presents two surfaces and two borders, 



