TABLE OF DEVELOPMENTS, ARTICULATIONS, ETC. 83 



buccinator, and masseter; by the internal surface, also commencing at the 

 symphysis, the genio-hyo-glossus, genio-hyoideus, mylo-hyoideus, digas- 

 tricus, superior constrictor, temporal, external pterygoid, and internal 

 pterygoid. 



fable showing the Points of Development, Articulations, and Attachment 

 of Muscles, of the Bones of the Head. 



SUTURES. 



The bones of the cranium and face are connected with each other by 

 means of sutures (sutura, a seam), of which there are four principal varie- 

 ties serrated, squamous, harmonia, and schindylesis. 



The serrated suture is formed by the union of two borders possessing 

 serrated edges, as in the coronal, sagittal, and lambdoid sutures. In these 

 sutures the serrations are formed almost wholly by the external table, the 

 edges of the internal table lying merely in apposition. 



The squamous suture (squama, a scale) is formed by the overlapping of 

 the bevelled edges of two contiguous bones, as in the articulation between 

 the temporal and the lower border of the parietal. In this suture the ap- 

 proximated surfaces are roughened, so as to adhere mechanically with 

 each other. 



The harmonia suture (a^sn/, to adapt) is the simple apposition of conti- 

 guous surfaces, the surfaces being more or less rough and retentive. This 

 suture is seen in the connection between the superior maxillary bones, or 

 of the palate processes of the palate bones with each other. 



The schindylesis suture (a-%w5\j\v)ft$, a fissure) is the reception of one bone 

 into a sheath or fissure of another, as occurs in the articulation of the ros- 

 trum of the sphenoid with the vomer, or of the latter with the perpendicular 

 lamella of the ethmoid, and with the crista nasalis of the superior maxil- 

 lary and palate bones. 



The serrated suture is formed by the interlocking of the radiating fibres 

 along the edges of the flat bones of the cranium during growth. When 

 this process is retarded in the infant by over- distension of the head, as in 

 hydrocephalus, and sometimes without any such apparent cause, distinct 

 ossific centres are developed in the interval between die edges; and, bein 

 surrounded by the suture, from independent pieces, which are called ossa 



