Hypothesis 3: Both legs are fractured from the trauma, additionally spinal nerve 
damage/hind leg nerve damage.

Instability of the right tibia leads us to believe that bone may have been fractured by the 
accident. 
Abnormal movement of limb, crepitation and extreme swelling of left hind limb led us to 
believe that a bone in the upper left hind leg is fractured.  Since this could not be 
localized by our initial orthopedic exam, we hypothesize that it could either be the upper 
femur, the hip joint itself or the pelvis.  Since the upper femur is at the level of a bumper 
of a car, it is a common bone broken when the dog is hit.
Motor function and pain sensation in both legs is present so nerve damage is not likely, 
however it could explain the inconsistency of the orthopedic exam (not consistent, 
nonrepetitive).