Hypothesis 1:


	The tendons that can be involved if there was injury to this area 
include extensor carpi radialis, the triceps, tensor fasciae antebrachii, and the 
anconeus.  All of these muscles are extensors of the elbow joint and the 
forearm.  Some of these muscles have attachments to the proximal part of 
the humerus, and insertions either at he distal part of the humerus or the 
proximal part of the ulna and radius.  So if there were a fracture to the 
middle part of the humerus, this would leave many of these muscles unable 
to extend the limb.  Also many times with a fracture in this location there 
also would be damage to the radial nerve.  This would explain the 
appearance of the “dropped elbow” and also would explain why the foal is 
unable to extend or place weight on the forelimb.  
	The muscle atrophy of the shoulder muscles is due to the lack of use 
over the past two weeks.  It takes about ten days for muscles to atrophy 
when an animal is not using them, and this does fit this time frame.  There 
may also be damage to the median nerve that runs in the same general area 
of the radial nerve.  You can loose innervation to many or all of the nerves 
of the forelimb except the radial nerve, and still be able to walk.  This is 
another piece of supporting evidence that there is damage to the radial nerve.  
In the history it said that the animal was able to place weight on the leg 
when standing, but from the pictures we were shown it does not look like the 
animal was placing any weight on the limb.