142 A MANUAL OF ANATOMY 



known as the gonion. The point, situated at the angle which 

 the posterior border of the frontal process of the malar makes with 

 the superior border of its zygomatic process, is known as the jugal 

 point. 



The sutures in this region are the fronto-malar, spheno-malar, 

 fronto-sphenoidal, spheno-parietal, squamo-sphenoidal, coronal, 

 squamous or squamo-parietal, temporo-malar (zygomatic), parieto- 

 mastoid, and a portion of the occipito-mastoid. 



The point where the superior temporal ridge crosses the coronal 

 suture is known as the stephanion, and the point where the 

 parieto-mastoid, occipito-mastoid, and lambdoid sutures meet is 

 known as the asterion. The latter coincides with the position of 

 the postero-lateral fontanelle in early life. The point near the 

 anterior part of the parieto-mastoid suture, where a process of 

 the parietal is received into the parietal notch of the mastoid, is 

 known as the entomion. 



The lateral region is divided by the zygomatic arch into the 

 temporal and zygomatic fossae, the former being above the arch, 

 and the latter within and below it. 



The temporal fossa is bounded above by the superior temporal 

 ridges of the frontal and parietal, and below by the upper border 

 of the zygomatic arch externally, and the infratemporal crest of 

 the great wing of the sphenoid internally. It is formed by five 

 bones, as follows : in front by the orbital process of the malar, 

 above by the lower portions of the frontal and parietal, and 

 below by the temporal division of the outer surface of the great 

 wing of the sphenoid and the squamous portion of the temporal. 

 The place where the parietal, frontal, great wing of the sphenoid, 

 and squamous portion of the temporal are related to one another, 

 and more particularly the region of the spheno-parietal suture, 

 is known as the pterion, which coincides with the position of 

 the antero-lateral fontanelle of early life. In this situation a Wor- 

 mian bone is sometimes present, called the epipteric bone. The 

 temporal fossa gives origin to the temporal muscle as high as the 

 inferior temporal ridge, and the temporal fascia, which covers 

 that muscle, is attached to the superior temporal ridge. 



The zygomatic fossa is situated below the level of the infra- 

 temporal crest of the sphenoid. It is bounded externally by the 

 ramus of the inferior maxilla and the inner surface of the zygomatic 

 arch, and, between the two, it communicates with the exterior by 

 means of the sigmoid notch. Internally it is bounded by the 

 external pterygoid plate of the sphenoid. Superiorly it is limited 

 by the zygomatic surface of the great wing of the sphenoid 

 below the infratemporal crest, where it presents the foramen 

 ovale and foramen spinosum, and by a small part of the 

 squamous portion of the temporal. Anteriorly its wall is formed 

 by the lower portion of the internal surface of the malar and the 

 zygomatic surface of the superior maxilla, which latter presents 

 the openings of the posterior dental canals. Its superior limit is 



