152 SKELETON. 



nexion with muscles and bones: besides which, there is a con- 

 siderable number of large foramina and fissures in it for the 

 blood vessels and nerves. To guard against the weakness 

 arising from the latter arrangement, nature has given a very in- 

 creased thickness to the base, particularly where much pressure 

 from the weight of the head exists, and has applied unusually 

 broad surfaces of bone to each other to secure them from dis- 

 placement by concussion, and different kinds of violence. These 

 arrangements are particularly manifest at the junction of the 

 cuneiform process of the occipital bone with the body of the 

 sphenoid, which, in middle age, is anchylosed; at the lower 

 part of the lambdoidal suture; and at the margins of the pe- 

 trous portions of the temporal bones where they touch the con- 

 tiguous bones. Whence it results that the several fastenings of 

 the base of the cranium, and also of the upper maxilla, are so 

 complete and strong, that they are most generally perfectly ex- 

 empt from dislocation; and when the violence offered to them 

 is sufficiently great, the bones, in place thereof, are fractured. 



The use of the sutures, in the cranium and upper maxilla, is 

 somewhat problematical; for as none of the bones move, the 

 head might have been equally well arranged by being made of 

 a single piece. In proof of which it is only necessary to recol- 

 lect, that in the very aged there is frequently not a bone of the 

 cranium and upper maxilla to be found in an insulated state: 

 they are all fused into the adjoining bones, by the obliteration 

 of their sutures. The old notion that sutures existed for the 

 purpose of arresting the course of fractures, and for opening in 

 some diseased conditions of the brain, has been very justly ex- 

 ploded. We know lhat a fracture will traverse a suture readily, 

 and that the opening of the sutures from hydrocephalus is an 

 occurrence only of very early infancy, where the sutures have 

 not arrived at the serrated and dove-tail arrangement, by which 

 they are subsequently secured. It is much more probable that 

 the true reason for the existence of sutures, is found among the 

 laws peculiar to the growing state; and which most commonly 

 are suspended after the several developments have been accom- 

 plished. Thus, the head, in consequence of being separated by 

 sutures into many pieces, is more readily wrought from its form 

 and size in the embryo state, to the form and size required by 



