32 HUMAN ANATOMY. 



The sutures of the face are very numerous, but the most 

 important are : 



Zygomatic, at the temporo-malar junction; 



Transverse, passes from one external angular process to the other, 

 and connects the frontal with the malar ethmoid, sphenoid, lachrymal, 

 superior maxillary, and nasal bones; 



Intermaxillary, the median suture between the superior maxillae; 



Symphysis, the remains of a foetal suture. 



The fontanelles are six membranous intervals in the infant's 

 skull corresponding to the four angles of the parietal bones. 

 The anterior, larger and lozenge-shaped, is at the junction of 

 sagittal and coronal sutures ; the posterior, smaller and triangu- 

 lar, is at the junction of sagittal and lambdoid sutures ; and the 

 four lateral are at anterior and posterior inferior angles of 

 parietal bones. 



The Wormian, or supernumerary, are irregular bones inter- 

 posed in intervals between the cranial bones, chiefly in the course 

 of the lambdoid suture. From their triangular form they are 

 called "ossa triqueta." 



Congenital fissures from an arrest of ossification also occur, 

 the most common being the parietal and sagittal fissures 

 (Treves). 



FOSSAE OF SKULL. 



The fossaB at the lateral regior of the skull are temporal, 

 zygomatic, and spheno-maxillary. 



Temporal Fossa. Deeply concave in front, convex. behind, 

 it is formed by parts of five bones frontal, malar, sphenoid, 

 temporal, and parietal. It is bounded above and behind by 

 temporal ridge; in front by the sphenoid, malar, and frontal; 

 below and externally by zygoma and pterygoid ridge on greater 

 wing of sphenoid. It is crossed by six sutures spheno-malar, 

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

 and transverse facial. It opens below into the zygomatic fossa, 

 is filled by the temporal muscle, and lodges the deep temporal 

 vessels. 



Zygomatic Fossa. This irregular cavity contains parts of 

 temporal, external and internal pterygoid muscles, and is bounded 

 above by pterygoid ridge of sphenoid and squamous portion of 

 temporal, below by alveolar border of superior maxilla, in front 

 by tuberosity of superior maxillary, behind by border of pterygoid 

 process, externally by zygoma and ramus of lower jaw, and in- 

 ternally by external pterygoid plate. It is traversed by two fis- 

 sures spheno-maxillary and pterygo-maxillary. 



