THE TEMPORAL BONE 



139 



The Squama (squama temporalis). The squama forms the anterior and upper 

 part of the bone, and is scale-like, thin, and translucent. 



Surfaces. Its outer surface (Fig. 137) is smooth and convex; it affords attach- 

 Eient to the Temporalis muscle, and forms part of the temporal fossa; on its hinder 

 part is a vertical groove for the middle temporal artery. A curved line, the tem- 

 poral line, or supramastoid crest, runs backward and upward across its posterior 

 part; it serves for the attachment of the temporal fascia, and limits the origin 

 of the Temporalis muscle. The boundary between the squama and the mastoid 

 portion of the bone, as indicated by traces of the original suture, lies about 1 cm. 

 below this line. Projecting from the lower part of the squama is a long, arched 

 process, the zygomatic process. This process is at first directed lateralward, its 

 two surfaces looking upward and downward; it then appears as if twisted inward 



Groove for middle 

 temporal artery 



Parietal notch 



Suprameatal 

 triangle 



OCCIPITALIS 



Articular tubercle 

 Post-glenoid process 



Petrotympa me fissure 

 Vaginal process 





Occipital groove 

 Tympanic part 

 STYLOHYOIDEUS 



Styloid process 

 FIG. 137. Left temporal bone. Outer surface. 



upon itself, and runs forward, its surfaces now looking medial ward and lateralward. 

 The superior border is long, thin, and sharp, and serves for the attachment of the 

 temporal fascia; the inferior, short, thick, and arched, has attached to it some 

 fibers of the Masseter. The lateral surface is convex and subcutaneous; the medial 

 is concave, and affords attachment to the Masseter. The anterior end is deeply 

 serrated and articulates with the zygomatic bone. The posterior end is connected 

 to the squama by two roots, the anterior and posterior roots. The posterior root, a 

 rolongation of the upper border, is strongly marked; it runs backward above the 

 external acoustic meatus, and is continuous with the temporal line. The anterior 

 root, continuous with the lower border, is short but broad and strong; it is directed 

 medialward and ends in a rounded eminence, the articular tubercle (eminentia 

 articiilaris) . This tubercle forms the front boundary of the mandibular fossa, 





