Learning Issues:

* What is a dropped elbow?  What does it look like?  The elbow joint is lowered from the body.  
* What causes a dropped elbow?  Radial nerve damage, fracture of ulna/humerus, bicipital bursitis.
* What muscles are innervated by the radial nerve?  Triceps, extensor carpi radialis, ulnaris lateralis, common and lateral digital extensors.
* How would the breed (Quarterhorse) affect an injury?  They are well-muscled and very athletic horses.  An injury could be masked by the large amounts of muscles in the area.
* Can a horse get up with only one front leg?  Yes.  It will be more difficult.