Hypothesis 1: Trauma causing damage to tendons

The mare stepped on the foalÕs right hind leg.  Abrupt change in angulation of the fetlock 
from the weight of the mare may have led to improper stretching of the tendons.  This 
may have triggered pain sensors in the insertion of the tendons and/or in the muscles 
associated with them.  There is also a vascular response resulting in capillary 
hemorrhage, fibrin deposition, and neutrophil, macrophage, fibroblast recruitment.