Winging scapula is the description for a condition where the shoulder blade
protrudes from your back, giving the impression of a wing. In most cases, only
one shoulder blade is affected. However, although less common, it can affect both
shoulder blades at the same time.
Why does winging scapula happen?
A variety of causes, ranging from injury to muscle dysfunction and nerve damage
can lead to winging scapula. Because it is often symptomatic of another
condition, evidence of a winging scapula should be investigated carefully and
The shoulder blade itself (scapula) is the largest bone in your shoulder and has
the greatest number of muscles attached to it. Each muscle works together to
enable you to move your arm in different directions. If any individual muscle fails
to work correctly, it can lead to dysrhythmia, which is a break in the rhythmic
motion of your shoulder blade. This can prevent the muscles from supporting
your shoulder blade properly and lead to a 'winging' of your scapula.
The classic cause of winging scapula is the dysfunction of a muscle called the serratus anterior muscle. This is an uncommon condition which arises out of damage to the long thoracic nerve which supplies the serratus anterior muscle.
An injury, or a lesion leading to inflammation, may cause damage to the nerve (e.g. Parsonage Turner Syndrome also known as brachial neuritis). Damage to the spinal accessory nerve in the neck will result in paralysis of the trapezius muscle and will also result in a type of winging of the scapula.
Winging scapula can also be a symptom of another condition. For example, if you have dislocated your shoulder several times, the muscles that move and support your shoulder blade may become damaged or prone to dysfunction.
Sometimes, if you have pain in another part of your shoulder, you may find yourself compensating for it by moving or holding yourself in an unnatural posture. This could in turn lead to a weakening of the muscles that support your shoulder blade.
How common is it?
Winging scapula is actually very common, but because it often causes no pain or other symptoms, it can tend to get overlooked.