Ok...well we think we know what is going on. My vet emailed this morning and said he is thinking it is something called "Sweeney". I did some research on this, and here's some of it:
Sweeney is the common name for shoulder atrophy (shrinkage or wasting) in the horse. The muscle atrophy is caused by damage to the suprascapular nerve which innervates to the infraspinatus and supraspinatus muscles. These muscles are found on the scapula or shoulder blade of the horse, on either of the spine or bony ridge of the scapula. When these muscle atrophy, the shape of the scapula becomes noticeable by the hollowing on each side of the spine of the scapula. The pictures below illustrates the loss of muscle on the shoulder blade and the distict spine of the scapula.
The nerve damage is commonly caused by horses colliding with other horses or objects.....ie stall doors, trees...etc. Nerve damage is also caused by ill fitting work collars putting pressure on the nerve. This is seen in horses which are used to pull wagons, carts and freight.
Pain may or may not be present in the affected limb. As the muscles atrophy worsens, the horse may have difficulty extending the forelimb. Also, horses may swing their shoulder out due to instability or loosening of the shoulder joint from lack of muscle and ligament tone.
Treatment of sweeney involves anti-inflammatories and physical therapy. Nerves can heal and possibly even regenerate if the injury is not too extensive and enough time is allowed. Muscle massage and electrical stimulation has been used. For cases with extensive scarring, surgery can be performed to release the nerve and hopefully regain function. In the case of a poorly fitted collar, rest and a properly adjusted collar is indicated.
I read another blog and other people were talking about some of their horses that were diagnosed with sweeney shoulder and they used chiropractics, equine massage therapy, and others. I hope the vet comes back with some not so expensive treatment plans...
