FRACTURE OF THE TIBIA. 
701 
became separated. In such cases the fracture is probably subfascial, 
a view supported by the commonly-observed fact that the fragments 
show no callus formation. Or, again, the primary injury may produce 
local or green-stick fracture, which weakens the tibia, but only gives 
rise to complete fracture under severe strains, like those occurring 
when rising, lying down, &c. Abrasion of the edges of fragments 
either results after fracture is complete or is due to subperiosteal frac¬ 
ture, in which slight movement of the fractured portions is possible. 
The absence of abrasion is not, however, evidence that green-stick 
fracture may not have existed for some considerable time, a fact of much 
forensic importance. A kick on the inner surface of the tibia, such as 
would be given by a horse standing on the opposite side, may at once 
produce complete fracture, which is then generally complicated. The 
bone is occasionally broken by the animal slipping, falling, being struck 
with the carriage-pole during collisions, or by its struggling violently in 
hobbles, as, for example, during castration, though, in the latter case, 
the femur or vertebral column is more often fractured. 
With the exception of the horse, the commonest sufferers from 
fracture of the tibia are dogs, in which the accident is due to being 
kicked, run over, &c. Oxen and other animals are much less frequently 
affected; nevertheless, cases are seen in them, and the practitioner is 
even occasionally called on to treat parrots and canaries. Fenimore 
describes a case of fracture of the tibia in a foetus ; the fracture had 
actually been produced by a kick received by the mother (a cow) whilst 
pregnant, and when the calf was born the fracture was united. 
The symptoms vary according to the degree of the fracture. 
Complete fracture renders it impossible to place weight on the limb, the 
unusual mobility of which can be detected even from a distance ; the 
foot, when lifted, remains dangling, and in the horse the condition shows 
some resemblance to rupture of the flexor metatarsi muscle. Fracture 
of the tibia, however, is at once differentiated by the impossibility of 
placing weight on the limb. 
In complete fracture, crepitation can always be detected. Not infre¬ 
quently the exact point of fracture is discoverable, especially if low in 
the leg. Perforation of the skin by splinters of bone removes the last 
doubts of fracture; in such case traces of the external injury are 
generally apparent. 
Fissuring sometimes, though not invariably, produces well-marked 
lameness, both when weight is placed on the limb and when it is 
carried. Starting from the injured point on the tibia, the line of fissure 
may be mapped out by the existence of pain over it. Fissures in the 
subcutaneous regions of the tibia may be diagnosed with certainty, 
otherwise they can only be guessed at, for this linear distribution of 
