Overview Snapshot A 47-year-old woman is undergoing an elective mastectomy with axillary node dissection after being diagnosed with breast cancer and having clinically positive axillary lymph nodes. On post-operative follow-up the patient's major concern is pain and weakness of the right shoulder. She reports that her husband noticed asymmetry in her shoulder blades. On physical exam, there is winging of the scapula when she is pushing against the wall. Introduction Anatomy arises from the 5th, 6th, and 7th cervical nerve roots that innervates the serratus anterior muscle the long thoracic nerve is a pure motor nerve Clinical correlate injury to the long thoracic nerve results in winging of the scapula which can be demonstrated when the patient presses against the wall which leads to the affected scapula projecting out etiologies include neuralgic amyotrophy this is an inflammatory disorder affecting the brachial plexus trauma to the nerve examples include a direct blow to the shoulder or the lateral chest wall (e.g., football) surgical procedures such as resection of the first rib mastectomy with dissection of the axillary node infraclavicular plexus anesthesia stretch or traction of the nerve can occur with repetitive motion when doing sports or physical labor