Shoulder Injuries in the Performing Arts: "Separations"

This is the second article in a series on shoulder injuries in the performing arts. This series of articles will address fairly damaging acute shoulder injuries. Unless otherwise noted, these injuries are substantial enough that they should not be self-treated until after you've seen a medical professional who has instructed you to do so. These traumatic shoulder injuries should be treated as emergencies, since there is a high risk of significant complications if they are improperly or incompletely cared for (these complications can include nerve damage, internal bleeding, and nonunion fractures). Some of the injuries discussed in this series can be caused by accidental falls or collisions, but these articles will focus on other mechanisms of injury.

The first article in this series discussed shoulder dislocations. It also cleared up some commonly confused terminology. To help you understand everything in this article, the Terminology section of the previous article is reprinted here:

“When it comes to shoulder injuries, there is often some confusion surrounding terminology. Some of this is due to the use of the word "shoulder" as a bit of a catch-all term to describe the entire interconnected system spanning from the center of the body to the upper arm (in front and back). Remember the kids' song that goes "the hip bone's connected to the...thigh bone....")? Turns out, it's (mostly) true - everything's connected.

The true shoulder joint is the glenohumeral joint - the ball and socket joint between the upper arm bone and the trunk. The scapula, also called the shoulder blade, is part of the glenohumeral joint, forms a joint with the collarbone, and is connected to the spine through muscles in the upper back. Muscles in the chest, neck, and upper and lower back direct the positioning and movement of the true shoulder joint. Therefore, thinking of the shoulder joint in isolation from the rest of the regions of the body that affect it is not only difficult, but it makes no sense. This is why medical professionals use the term "shoulder girdle" to describe the entire system surrounding the shoulder joint, including the collar bone, shoulder blade, humerus (upper arm bone), spine, and all of the muscles associated with the shoulder.

So, while "dislocated shoulder" and "separated shoulder" sound like they are very similar injuries to the same body part - and are often confused or used interchangeably - they actually are very distinct injuries to entirely different structures within the shoulder girdle. The treatment and long-term effects of the following injuries are very different, so early - and correct - identification of an acute injury to the shoulder is essential to a complete recovery.”

This article discusses “shoulder separations.”

Shoulder Separation

What you feel

Shoulder “separations” are caused by acute trauma more frequently than through chronic overuse of the joint and surrounding area. However, with both low-grade acute “separations” and chronic injuries, you may not be able to point to one specific incident that caused the injury. Your symptoms may not appear until a few minutes to a few days later. More severe acute shoulder “separations” are almost always caused by a direct blow to the shoulder (a collision or falling onto the shoulder) or falling onto an outstretched arm (or a bent elbow) and, therefore, will not be discussed here.

Regardless of whether you suffer a mild acute injury or a chronic one, the most noticeable thing you experience when you “separate” your shoulder is pain located at the “tip” of your shoulder (where your collarbone and shoulder blade come together at the front of your shoulder). Other common symptoms include:

• Pain over:
• The far end of the collarbone (distal clavicle)
• The front and side of the neck
• The upper part of the shoulder blade (superior scapula)
• The muscle on the “outside” of the shoulder (the deltoid)
• Pain with nearly all arm motions, especially those elevating the arm above the height of the shoulder joint
• Pain that radiates into the shoulder blade and neck
• Tenderness over the tip of the shoulder (the acromioclavicular joint)
• Decreased strength with all arm motions

You may also notice that the end of your collarbone (distal clavicle) moves more than it did pre-injury and/or that it is displaced.

The main differences between a chronic shoulder “separation” and an acute one, in terms of how you experience them, are:

1. With a chronic injury, there is no history of a traumatic injury to the area.
2. The acromioclavicular joint is not unstable with a chronic injury, despite being painful.

What happens to your body

The phrase “shoulder separation” is used to describe a sprain of one or more of the ligaments that surround, stabilize, and support the acromioclavicular (AC) joint of the shoulder. The AC joint is the junction between the acromion process of the scapula (shoulder blade) and the distal end (the end further away from the midline of the body) of the clavicle (collar bone). AC joint sprains result in instability or even dislocation of the joint.

These injuries can have long-lasting effects for a couple of reasons:

1. Once a ligament is stretched, it does not return to its pre-injury resting length. This reduces the ligament’s ability to stabilize the joint, which puts the joint at risk of developing chronic inflammation or suffering a joint dislocation in the future.
2. Your collarbone tilts, elevates, and rotates every time you take a breath. This makes it very difficult for injured tissues to heal properly since they are being moved constantly. This not only extends the amount of time needed to heal from severe injuries, but it also can prolong the amount of time you experience pain from the initial injury.

How it can happen in the performing arts

The most common way the AC joint is sprained is through separation of the acromion process (on the shoulder blade) and the clavicle (collarbone). This is why the term “separated shoulder” came into existence. This can result in the two bones moving away from each other in any way, but the AC joint is most frequently injured when a direct impact on the tip of the shoulder forces the acromion process downward, backward, and inward while pushing the clavicle down against the rib cage.

Acute AC joint sprains are most likely to occur in the performing arts during:

• Dance involving partnering (missed shoulder catches for the person “catching”)
• Dance or acting involving floor dives or other floor work (landing on a forward-flexed outstretched arm or the point of the elbow, landing directly on the tip of the shoulder, having someone else land on your shoulder/collarbone while you’re on the floor)
• Marching band for sousaphones and drumline (AC sprains usually occur away from performances/rehearsals. They typically occur while carrying the instrument off to one shoulder and having it slip or hit something that forces it down into your shoulder, or by putting the sousaphone on too carelessly and having it slam into the tip of the shoulder)
• Stage crew lifting or moving objects overhead (an object falls onto the tip of the shoulder)

The AC joint can also be subject to overuse injuries caused by less-traumatic versions of the mechanisms described above. Lightly hitting the tip of your shoulder on the floor 5-10 times per rehearsal several times per week for 2 months can lead to chronic inflammation and many of the same symptoms experienced with an acute AC joint sprain.

Watch for the next article in the shoulder injury series. While you’re waiting, be sure to read about shoulder dislocations in the first article of this series.