Hypothesis 3b tendon/ligament injury Laceration or damage to either the suspensory ligament or the superficial digital flexor would make the foal extremely sensitive. As a result the animal is hesitant to place full weight on itÕs foot because this stretches the tendons and is painful. To avoid the associated pain the animal stands on itÕs toe. Weakening of the tendon may be initiated by ischemia (the curtailment of blood supply) with exercise, or in this case from being stepped on by the mare. Vessel rupture can occur causing ischemia. Collagen breakdown within the tendon initiates inflammation by attracting inflammatory mediators. Signs characteristic of tendonitis include lameness, swel- ling, increased heat, and pain on palpation. In mild to moderate injury, heat and swelling are the first signs. In both moderate and severe injury, degeneration of the tendon fibers can occur over time. Ultrasound often demonstrates a progressive lesion over several days to weeks. In mild injuries, tendons may show heat and only mild swelling with no lameness. Often this is resolved in 24 to 48 hours. If exercise or weight-bearing continues, the tendon frequently is re-injured, which results in permanent swelling and pain."