THE SUTURES. 57 



cranium : the two ossa parietalia form the upper and middle 

 part of it ; the ossa temporum compose the lower part of the 

 sides ; the os occipitis makes the whole hinder part and some 

 of the base ; the os ethmoides is placed between the orbits of 

 the eyes, and the sphenoides extends across the base of the 

 cranium. 



The Sutures. 



The above bones are joined to each other by five sutures ; the 

 names of which are the Coronal, Lamhdoidal, Sagittal, and 

 two Squamous. 



The coronal suture is extended over the head, from within 

 about an inch of the external angle of one eye, to the like dis- 

 tance from the other ; which being near the place where the 

 ancients wore their garlands, this suture has hence got its 

 name. Though the indentations of this suture are conspicuous 

 in its upper part, yet an inch or more of its end on each side 

 has none, but is squamous and smooth. 



The lamhdoidal suture begins some way below, and further 

 back than the vertex or crown of the head, whence its two legs 

 are stretched obliquely downwards, and to each side, in form 

 of the Greek letter a? and are now generally said to extend 

 themselves to the base of the skull ; but formerly, anatomists 

 reckoned the proper lamhdoidal suture to terminate at the 

 squamous sutures : and the portion continued from them on each 

 side, where the indentations are less conspicuous than in the 

 upper part of the suture, they called additamentum suturae 

 lambdoidis. 



This suture is sometimes very irregular, being made up of a 

 great many small sutures, which surround a number of insulated 

 bones, that are generally more conspicuous on the external 

 surface of the skull than internally. These bones are commonly 

 called triquctra or wormiana ; their formation is owing to a 

 greater than ordinary number of points of .ossification in the 

 skull, or to the ordinary bones of the cranium not extending 

 their ossification far enough or soon enough ; in which case, 

 the unossified interstice between such bones begins a separate 



