winged scapula is associated with damage or a contusion to the long thoracic nerve of the shoulder and / or weakness in the Serratus Anterior muscle. If the long thoracic nerve is damaged or bruised it can cause paralysis of the serratus anterior muscle and winging of the scapular or shoulder blade. 

During my very first surgery – the lumpectomy – a nerve was accidentally cut on my left shoulder area. I have significant loss of range of motion left arm, with a constantly stiff arm and shoulder.  Left hand grip strength tests at half of right hand strength.