174 



THE SKELETON. 



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

 Temporal muscle, and marks the boundary between the squamous and mastoid 



process. 

 FIG. 138. Left temporal bone. Outer surface. 



portions of the bone. Projecting from the lower part of the squamous portion is a 

 long, arched process of bone, the zygoma or zygomatic process. This process is 

 at first directed outward, its two surfaces looking upward and downward ; it then 

 appears as if twisted upon itself, and runs forward, its surfaces now looking in- 

 ward and outward. The superior border of the process 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 fibres of the Masseter muscle. Its outer surface 

 is convex and subcutaneous ; its inner is concave, and also affords attachment to the 

 Masseter. The extremity, broad and deeply serrated, articulates with the malar 

 bone. The zygomatic process is connected to the temporal bone by three divisions, 

 called its roots an anterior, middle, and posterior. The anterior, which is short, 

 but broad and strong, is directed inward, to terminate in a rounded eminence, the 

 eminentia articularis. This eminence forms the front boundary of the glenoid 

 fossa, and in the recent state is covered with cartilage. The middle root (post- 

 glenoid process) forms the posterior boundary of the mandibular portion of the 

 glenoid fossa; while the posterior root, which is strongly marked, runs from the 

 upper border of the zygoma, in an arched direction, upward and backward, form- 

 ing the posterior part of the temporal ridge (supramastoid crest). At the junction 

 of the anterior root with the zygoma is a projection, called the tubercle, for the 

 attachment of the external lateral ligament of the lower jaw ; and between the ante- 

 rior and middle roots is an oval depression, forming part (mandibular) of the glenoid 

 fossa (yAjJwp, a socket), for the reception of the condyle of the lower jaw 7 . This fossa 

 is bounded, in front, by the eminentia articularis ; behind, by the tympanic plate and 

 the auditory process ; and is divided into two parts by a narrow 7 slit, the Glaserian 

 fissure. The anterior or mandibular part, formed by the squamous portion of the 

 bone, is smooth, covered in the recent state with cartilage, and articulates with the 

 condyle of the lower jaw. This part of the glenoid fossa is separated from the audi- 

 tory process by the post-glenoid process, the representative of a prominent tubercle 



