Sweeney Shoulder in Horses | PetMD

What is Sweeney Shoulder in Horses?

Sweeney’s shoulder in horses, also known as suprascapular neuropathy, is characterised by atrophy (wasting) of the horse’s shoulder muscles.

Sweeney shoulder in horses is more commonly heard among horse owners today than it was hundreds of years ago, when the horse’s primary role was transportation.

At the time, horses wore heavy harnesses to pull carts and buggies, and these harnesses often compressed or injured the suprascapular nerve in the horse’s shoulder blade, ultimately leading to muscle damage and muscle atrophy.

Symptoms of Sweeney’s Shoulder in Horses

The most common symptoms of sweeney shoulder in horses are:

• Muscle weakness

• Hollow around the shoulder blade

• The shoulder blades become more prominent

• Looseness of the shoulder joint or dislocation of the shoulder

• Other muscles in the upper leg may “weaken,” causing symptoms such as dragging your toes or “popping” in your shoulders.

• pain

• inflammation

• Lameness

• Reluctance to move the affected limb forward

All cases of Sweeney’s shoulder involve wasting of the shoulder muscles, and in severe cases, the muscles are lost, causing the shoulder blade to protrude.

Causes of Sweeney Shoulder in Horses

Sweeney’s shoulder in horses is considered to be a syndrome because it describes the physical appearance of the horse’s shoulder rather than a diagnosis.

The causes of Sweeney Shoulder are varied, but the most common cause is injury to the suprascapular nerve. This injury can be acute (such as being kicked in the shoulder) or chronic (such as wearing an ill-fitting harness). The suprascapular nerve provides a vital connection to important muscles in the shoulder. When this nerve does not function properly, the muscles atrophy and do not function properly.

Other causes of sweeney shoulder in horses include:

• Disuse atrophy (not using muscles)

• Brachial plexus injuries (which typically affect multiple nerves and muscle groups from the neck through the shoulders and front legs)

• Caudal neck disease causing spinal radiculopathy (lower neck disease causing compression of the spinal nerves)

• Injuries and diseases of the lower limbs Laminitis

• Poor recovery from anesthesia – blood flow does not return to normal after the horse has been laid down (reduced blood flow to tissues) because the anesthesia or medication is still affecting the body

How Veterinarians Diagnose Sweeney’s Shoulder in Horses

Diagnosis of Sweeney’s Shoulder often includes a physical exam and taking radiographs (X-rays) to rule out fractures of the forelimb or shoulder blade. During the physical exam, your veterinarian will look for muscle wasting in the shoulder or changes in muscle mass compared to the other side. Your veterinarian may also feel or look to see if there are abnormal scapular spurs that may be due to muscle weakness.

Your veterinarian may also observe your horse’s gait and check the range of motion of the shoulder joint to assess for any laxity in the joint. In some cases, radiographs (x-rays) may be important in understanding the severity of Sweeney’s shoulder and determining a treatment plan.

Treating Sweeney’s Shoulder in Horses

The initial goal of treatment for sweeney shoulder is to reduce your horse’s pain and inflammation. Until that is under control, your horse will remain in its stall resting position. This is important not only for your horse’s comfort but also to encourage controlled movement. Medications your veterinarian may prescribe include: NSAIDs such as phenylbutazone (Bute), Equioxx® (Firocoxib), and Banamine® (Flunixin meglumine).

In addition to medical management, you can keep your horse’s muscles active by:

• Physical therapy

• acupuncture

• Chiropractic Therapy

• Electrical stimulation

These methods help maintain muscle activity, promote regeneration, and reduce further atrophy.

Once the horse is comfortable moving around, your veterinarian may implement a controlled exercise program. A controlled exercise program may consist of ground exercises such as lunging. As the horse recovers and makes a good recovery, the exercise program may be expanded to controlled riding. This will depend on the severity of the injury and how well the horse is recovering.

Sweeney Shoulder Surgery in Horses

In cases of severe atrophy or when medical management does not improve the condition, surgery may be recommended.

Surgery to remove part of the scapula and scar tissue may help relieve pressure on the nerve and promote healing. Surgery increases the risk of scapular fractures by weakening the bone, but this risk decreases as healing progresses.

Recovery and management of the Sweeney shoulder joint in horses

Recovery from Sweeney shoulder depends on the cause and severity.

If nerve function is severely affected, the shoulder joint may become unstable and may “pop” when the horse puts weight on the shoulder. This subluxation (partial dislocation) of the joint may not seem painful, but it does leave the joint unstable. This can have serious implications for the long-term health of the shoulder joint and the horse’s playing career.

Approximately 80% of horses with suprascapular nerve injuries will improve without surgical intervention, and most cases seem to recover over time, although it may take up to 12 months for full shoulder function to be regained and some muscle loss will remain.

The prognosis of Sweeney shoulder appears to be most influenced by the following factors:

• Duration of injury before diagnosis

• Severity of muscle wasting

• Ability to undergo physiotherapy treatment for several months

Sweeney’s shoulder, with or without treatment, can cause the following symptoms:

• Permanent muscle damage

• Permanent nerve damage

• Shoulder instability

• arthritis

• Chronic claudication

• Contralateral (opposite side of the leg affected by Sweeney’s shoulder) laminitis