Group 15
Hypothesis 2:  Traumatic fracture of the olecranon or  proximal  
ulna of the right front 
limb. 

     This foal presents with a Òdropped elbowÓ, swelling just distal 
to the shoulder 
musculature, slight  flexural contracture, mild atrophy  of the 
shoulder  musculature.   No 
instability or crepitance is felt.  The lameness is weight bearing 
when the foal is still and 
began 2 weeks ago.  Otherwise the foal is normal.  The owners 
believe he may have been 
kicked.  

  Though the foal does not show any lacerations in the region of the 
elbow or shoulder, we 
believe a kick from a pasture-mate (see hypothesis 1) has caused an 
incomplete fracture of either the olecranon 
or the proximal ulna.  As the olecranon is the point of attachment  
for all heads of the 
triceps  muscle and the tensor fasciae  antebrachii, any use of 
these muscles  would put 
tension on the olecranon  thereby  causing pain.   To avoid use of 
these muscles (extension 
of the elbow), the foal holds his elbow in a flexed position and 
completely relaxes his 
triceps, which caused the Òdropped elbowÓ presentation.  Because the 
foal is able to bear 
minimal weight while in a standing position and there was no 
apparent joint or bone 
instability, the fracture is most likely a nondisplaced, incomplete 
fracture of the olecranon.   
Though painful, it is possible that the location of the fracture 
sight would not compromise 
the weight bearing capacity of the ulna. There are no loose pieces 
of bone at the location of 
the fracture therefore crepitance is absent.    
    It is possible that the kick may have damaged the proximal 
radial physes.
    As the foal has kept his shoulder and upper arm in a stationary, 
relaxed position for 2 
weeks, the muscle fibers of the triceps have begun to shrink due to 
lack of use (atrophy).  The foal also 
appears to stand with the tip of his hoof resting on the ground.  
This position relieves some 
of the weight on his leg, but places his fetlock and pastern in a 
flexed position.  Over the 
two weeks, this position has probably stretched the extensor tendons 
while simultaneously 
allowing the flexor tendons to contract.
    Due to the direct trauma of the kick and the subsequent 
inflammation, blood vessels have 
leaked into the area (damaged vessel walls or increased permeability 
due to 
inflammatory mediators) causing edema.  The local release of 
prostaglandins causes pain.  
In the 2 weeks since the injury, the inflammation has probably 
subsided somewhat; the area 
did not present with heat.