Section VIII. FRACTURES
when a bone is subjected to more stress than it is able to absorb. Fractures may occur
from several specific causes and are categorized as follow.
(1) Direct force. In direct force fracture, a bone is subjected to more stress
than it can absorb from an impact with a solid object. For example: a direct blow, as
from a baseball bat, or a crushing force, such as some automobile accidents.
(2) Twisting. In a twisting (torsion) fracture, an indirect force may cause a
break in a bone at a location other than the site of the twisting force. This type of injury
is common in skiing accidents.
(3) Muscle contraction. In another indirect force fracture, powerful
contraction of a muscle may cause the muscles to tear away from the bone, often
fracturing or avulsing part of the bone in the process. This type of injury may occur
during a grand mal seizure. This type fracture is seen in soldiers in an injury known as
"grenade thrower's fracture." The humerus is fractured as a result of the muscular
contractions in throwing a hand grenade.
(4) Pathological fracture. Bones that have become weakened from age or
disease are easily fractured, often from just a slight movement.
(5) Fatigue or stress fracture. This type of injury may occur when a bone
has been subjected to repeated stress. This phenomenon is commonly associated with
sports enthusiasts and soldiers. The repeated stress of sustained running or marching
may cause stress fractures of the feet or lower extremities.
b. Sometimes it will be quite obvious that a bone is fractured, but this is not
always the case. An X-ray will often be necessary to make the diagnosis of fracture.
Specific signs and symptoms will vary according to the type and location of the fracture.
An open fracture with bone protruding from the wound is very obvious. In the case of a
closed fracture, however, a fracture will be more difficult to assess. Some signs and
symptoms associated with fractures are:
Deformity (visible or palpable).
False motion; abnormal mobility at the fracture site.