FBACTUBES OF THE SKULL. 101 



this ligament itself is lacerated, the portion of the tibia remain- 

 ing intact. 



Outward dislocation in these cases is apt to be much aggravated, 

 and the foot is considerably drawn upwards on the outer side of 

 the leg. 



Fractures of the Os Calcis. In a vertical fracture of the os 

 calcis near its posterior extremity, the hinder fragment is pulled 

 upwards by the action of the muscles attached by the tendo 

 Achillis. 



FRACTURES OF THE SKULL. 



These consist of (1) Fractures of the cranium. (2) Fractures 

 of the bones of the face. 



Injuries about the scalp, with which open fractures of the 

 vault of the skull are practically always associated, are of con- 

 siderable importance, and it may be as well to allude to them at 

 this point. 



Wounds of the Scalp. There are several anatomical facts 

 concerning wounds of the scalp which are of the greatest 

 importance. (See Fig. 4.) 



The tissues forming the scalp are the skin, thickly beset with 

 hairs, the subcutaneous tissue, the aponeurosis of the occipito- 

 frontalis muscle, the underlying loose areolar tissue and the 

 pericranium. 



Any wound which does not involve the aponeurosis is not 

 serious, except on account of haemorrhage and the liability of 

 superficial sepsis. The arteries lie in the dense subcutaneous 

 tissue, and when divided this tends to prevent them from con- 

 tracting and retracting. Hence the severe bleeding which is 

 likely to result, and the difficulty of controlling it either byforci- 

 pressure or by ligature. The underlying bone, however, will 

 enable pressure to be applied by the dressing and bandage, and 

 this will usually be sufficient to control the haemorrhage. 



When a scalp wound involves the aponeurosis, blood, or 

 inflammatory fluids such as pus, are liable to spread over the 

 vault of the skull, being limited only by the attachments of 



