ARTICULATIONS. 93 



at points where the pressure is most powerful, and increas- 

 ing at other points; tight lacing may in this way produce a 

 permanent distortion of the ribs. 



When a bone is fractured a surgeon should be called in 

 as soon as possible, for once inflammation has been set up 

 and the parts have become swollen it is much more diffi- 

 cult to place the broken ends of the bone together in their 

 proper position than before this has occurred. Once the 

 bones are replaced they must be held in position by splints 

 or bandages, or the muscles attached to them will soon dis- 

 place them again. With rest, in young and healthy per- 

 sons complete union will commonly occur in three or four 

 weeks; but in old persons the process of cure is slower and 

 is apt to be imperfect. 



Articulations. The bones of the skeleton are joined to- 

 gether in very various ways; sometimes so as to admit of no- 

 movement at all between them; in other cases so as to per- 

 mit only a limited range or variety of movement; and else- 

 where so as to allow of very free movement in many direc- 

 tions. All kinds of unions between bones are called articu- 

 lations. 



Of articulations permitting no movements, those which 

 unite the majority of the cranial bones afford a good exam- 

 ple. Except the lower jaw, and certain tiny bones inside the 

 temporal bone belonging to the organ of hearing, all 

 the skull-bones are immovably joined together. This union 

 in most cases occurs by means of toothed edges which 

 fit into one another and form jagged lines of union known 

 as sutures. Some of these can be well seen in Fig. 26* between 

 the frontal and parietal bones (coronal suture) and between 

 the parietal and occipital bones (lambdoidal suture)', while- 

 another lies along the middle line in the top of the crown 

 between the two parietal bones, and is known as the sagit- 

 tal suture. In new-born children where the sagittal meets 

 the coronal and lambdoidal sutures there are large spaces 

 not yet covered in by the neighboring bones, which subse- 

 quently extend over them. These openings are known as; 

 fontanelles. At them a pulsation can often be felt syn- 

 chronous with each beat of the heart, which., driving more 



*P. 74^ 



