During the physical examination, winging may or may not be obvious to the physician. . If weakness of the scapular muscles is not severe the condition can sometimes be less noticeable.
When the serratus anterior functions improperly, the scapula moves backward and wings when the arm is raised in front of the body into flexion.
If the trapezius muscle functions improperly, the scapula moves toward the opposite side and wings when the patient tries to raise the arm out to the side
Diagnostic Tests
The most important diagnostic test for scapular winging is called an electromyographic and nerve conduction study (EMG and NCS). This special test measures the electrical impulses coming down the nerves to the scapular muscles. Nerve injuries which cause winging prevent normal conduction of electrical impulses to the muscles, causing them to malfunction. When the serratus anterior is involved, the long thoracic nerve may be paralyzed. When the trapezius is involved, the spinal accessory nerve is damaged.
