104 CLINICAL APPLIED ANATOMY. 



a line, in the adult, drawn vertically upwards from the external 

 auditory meatus cuts it. From the bregma a line carried down- 

 wards and forwards to a spot called the pterion represents the 

 coronal suture. The pterion is placed on a line drawn backwards 

 from the external angular process of the frontal, parallel to the 

 zygoma, at a spot where a second line drawn upwards from the 

 middle of the zygoma cuts the first. 



The sagittal suture runs backwards in the middle line from 

 the bregma to the lambda, the latter being approximately placed 

 one-third the distance along the line leading from the bregma 

 to the inion, or external occipital protuberance. 



From the lambda down to the base of the mastoid process will 

 be found running the lamboid suture. The remaining suture is 

 the squamo-parietal, which forms a curved line with its convexity 

 upwards, starting from the level of the centre of the zygoma and 

 terminating at the base of the mastoid, the highest point of the 

 curve reaching about one-third the distance along the line passing 

 from the external auditory meatus to the bregma. 



Fractures of the vault occur in three forms the undepressed, 

 the depressed, and the elevated. 



In the undepressed, there may be a linear or stellate fissure 

 involving the whole thickness of the bone. The presence of 

 either of these as a closed or simple fracture cannot be absolutely 

 diagnosed, but only surmised. An open or compound linear 

 fracture has to be diagnosed from either a mere slit in the peri- 

 cranium without a break in the bone, or a suture exposed by the 

 scalp wound. A fracture may be diagnosed from a mere slit in 

 the pericranium chiefly by the fact that blood will well up 

 through the fissure from the diploe. From a suture a fracture 

 may be diagnosed by the same fact, and also that most of the 

 sutures exhibit a much greater irregularity because of their 

 serration. 



Particular care must be taken in scalp wounds of the temporal 

 region not to mistake the margin of the squamous portion of the 

 temporal bone, overlapping the lower border of the parietal, for 

 a fracture in this region. 



