er cases it involves only a portion of the
thickness of the bone, and for that reason is described as incomplete.
If the bone is divided into two separate portions and the soft parts
have received no injury, the fracture is a simple one, or it becomes
compound if the soft parts have suffered laceration, and comminuted if
the bones have been crushed or ground into fragments, many or few. The
direction of the break also determines its further classification.
Broken at a right angle, it is transverse; at a different angle it
becomes oblique, and it may be longitudinal or lengthwise. In a complete
fracture, especially of the oblique kind, there is a condition of great
importance in respect to its effect upon the ultimate result of the
treatment in the fact that from various causes, such as muscular
contractions or excessive motion, the bony fragments do not maintain
their mutual coaptation, but become separated at the ends, which makes
it necessary to add another descriptive term--with displacement. These
words again suggest the negative and introduce the term without
displacement, when the facts justify that description. Furthermore, a
fracture may be intra-articular or extra-articular, as it extends into a
joint or otherwise, and, once more, intra-periosteal when the periosteum
remains intact. Finally, there is no absolute limit to the use of
descriptive terminology in the case.

The condition of displacement is largely influential in determining the
question of treatment and as affecting the final result of a case of
fracture. This, however, is dependent upon its location or whether its
seat is in one or more of the axes of the bone, in its length, its
breadth, its thickness, or its circumference. An incomplete fracture may
also be either simple or comminuted. In the latter case the fragments
are held together by the periosteum when it is intact; in that case the
fracture belongs to the intra-periosteal class. At times, also, there is
only a simple fissure or split in the bone, making a condition of much
difficulty of diagnosis.

_Causes._--Two varieties of originating cause may be recognized in cases
of fracture. They are the predisposing and the occasional. As to the
first, different species of animals differ in the degree of their
liability. That of the dog is greater than that of the horse, and in
horses the various questions of age, the mode of labor, the season of
the year, the portion of the body most exposed, an