Q: I was trying on clothes at the mall the other day in front of those three-way mirrors. I noticed that one of my shoulder blades is sticking out. What could be causing this? Should I do anything about it?

A: What you may be seeing is something we call scapular winging. Scapula is another word for shoulder blade. Scapular winging, of course, describes the position of the scapula as it "sticks out."

Sometimes you see scapular winging in young children. They haven't developed the full strength of the arms and upper back yet. If they are skinny and all arms and legs, you might not think twice about the scapulae (plural for scapula and a scapula is the same as shoulder blade) sticking out.

But in adults, scapular winging (especially when it's only present on one side) isn't normal and can have some serious consequences. Without proper scapular positioning and movement, the arm doesn't move normally. Lifting the arm overhead and then lowering it back down can become painful, difficult, and even impossible.

What causes this problem and what can be done about it? Causes of scapular winging are broken down into two groups: primary and secondary. Primary scapular winging occurs when one of the main muscles that hold the scapula steady stops working as it should.

Injury to the nerve controlling scapular muscles is one cause of primary scapular winging. Athletes are at greatest risk for nerve paralysis causing primary scapular winging. Whether an athlete, homemaker, industrial worker or other individual who suffers a fall, collision, or repetitive motion, you could develop this problem.

Secondary scapular winging is the result of a problem somewhere else in the shoulder complex. That other problem could be a rotator cuff tear, shoulder bursitis, shoulder dislocation, or a frozen shoulder.

Any injury or condition that can alter the way the muscles fire or cause muscular fatigue can result in impairment of the scapular rhythm needed for normal arm movement. Likewise, anything that changes the alignment of the scapula can have the same effects on scapular position and movement.

Before defining the treatment, an accurate diagnosis and understanding of the cause is needed. An orthopedic surgeon or physiotherapist can help you with this. A review of your history and current activities will be conducted. A physical examination including observation of your movement patterns and testing of the muscles will be performed.

Most often, conservative (nonoperative) care is advised. Recovery and restoration of normal movement (and thus normal alignment of the scapula) can take several months up to several years depending on the underlying cause. Sometimes surgery is needed but that decision is way down the road for you at this point.

Reference: Alexander K. Meininger, MD, et al. Scapular Winging: An Update. In Journal of the American Academy of Orthopaedic Surgeons. August 2011. Vol. 19. No. 8. Pp. 453-462.