80 CLINICAL APPLIED ANATOMY. 



Pain is experienced at the seat of fracture owing to nerve 

 endings being torn or bruised ; pain may also be referred in 

 consequence of the irritation of nerve trunks implicated opposite 

 the fracture. 



A fracture which does not in any way communicate with the 

 outer air is said to be closed, or " simple." A fracture which 

 does communicate with the outer air, it matters not how, is said 

 to be open, or " compound." It is well to remember in this 

 connection that the track along which air and therefore septic 

 micro-organisms may reach the fractured ends of a bone may be 

 a very devious one. This is particularly so in bullet injuries, 

 where the wound of entrance may be very remote from the site 

 of fracture. 



Emphysema, or air in the tissues, may follow the fracture 

 of certain bones because of their anatomical position. Most 

 commonly it is found after fracture of the ribs because of a 

 co-existent wound of the underlying lung. Fracture of the nose 

 leads frequently to laceration of the nasal mucous membrane, 

 and thus to escape of air into the frontal tissues, as also will a 

 fracture involving the frontal sinus, or the antrum of Highmore. 

 Occasionally fractures of the hyoid are associated with escape of 

 air derived from the larynx, and fractures of the pelvis with 

 gas derived from the rectum. 



SPECIAL FRACTURES. 



Fractures of the Nasal Bones. The nasal bones forming the 

 roof of the nose are usually prominent and thus considerably 

 exposed to injury. The bones are to a certain extent protected 

 by the overhanging forehead, and supported by the septum and 

 nasal processes of the maxillse. Fracture is therefore most 

 commonly through the lower third where they are least supported. 

 A fracture caused by direct violence is usually accompanied by 

 laceration of the mucous membrane of the nasal fossa, even if 

 the skin is entirely untorn. Epistaxis follows ; frequently the 

 nose is blown to clear out the blood, and air may be thus forced 



