chap, i.) THE SCALP, 7 



often very slow to close, since its walls are prevented 

 from obtaining perfect rest by the frequent movement 

 of the epicranial muscle. To mitigate this evil, and 

 to ensure closing of the sinuses in obstinate cases, 

 Mr. Hilton advises that the whole scalp be firmly 

 secured by strapping, so that the movement of the 

 muscle is arrested. 



Abscess beneath the pericranitim must be limited 

 to one bone, since the dipping in of the membrane at 

 the sutures prevents a more extensive spreading of 

 the suppuration. 



Haematomata, or blood tumours of the 

 scalp region, occur in the same localities as abscess. 

 The extravasation of blood above the aponeurosis 

 must be of a limited character, while that beneath it 

 may be very extensive. It fortunately happens, how- 

 ever, that the cellular tissue between the aponeurosis 

 and the pericranium contains but very few vessels, 

 and hence large extravasations in this tissue are un- 

 common. 



Extravasations of blood beneath the pericranium 

 are generally termed cephalhsematomata, and are of 

 necessity limited to one bone. They are usually con- 

 genital, are due to pressure upon the head at birth, 

 and are thus most commonly found over one parietal 

 bone, that bone being probably the one most exposed 

 to pressure. Their greater frequency in male children 

 may depend upon the larger size of the head in the 

 male foetus. Such extravasations in early life are 

 encouraged by the laxity of the pericranium, and by 

 the softness and vascularity of the subjacent bone. 



In the temporal region, or the region corre- 

 sponding to the temporal muscle, the layers of soft 

 parts between the skin and the bone are somewhat 

 different from those that have been already described 

 as common to the chief part of the scalp. There is a 

 good deal of fat in the temporal fossa, and when this 



