Hypothesis 2
Injury leading to Inflammation

Possibility of mother stepping on fetlock region.  Damage resulting to superficial and/or 
deep digital flexor tendon, and tendon sheath.  Also, a bone fracture is possible.  More 
likely to be a hair line fracture due to lack of crepitation.  Inflammation resulting from the 
trauma causes a vascular and cellular response.  For the vascular response capillary 
hemorrhage and fibrin deposition separates fibers and weakens the remaining tendon 
fibers.  This can lead to stretching leading to pain.  The vasculature also becomes more 
permeable leading to the excape of fluids into the soft tissue causing swelling, and 
therefore pain due to stretching of the joint capsule.  The increased permability increases 
the influx inflammatory mediators, allowing the cellular response to occur, (neutrophils 
and macrophages migrate into the region).  The inflammation causes the release of 
prostaglandins, and other inflammatory mediators causing pain directly and indirectly by 
decreasing the pain threshold.
  
The severity of the lameness is assessed as being severe because the foal is lame at a 
walk.  

The lack of instability reduces the possibility of a ruptured tendon or ligaments.

The possibility of joint infection is decreased because of lack of crepitation and the fact 
that only one joint is involved.

The lack of foreign bodies in the joint capsule, or crepitation also decreases the 
possibility of a major joint fracture.