During a radical mastectomy, the long thoracic nerve must be carefully preserved to prevent which of the following complications? A) Weakness in shoulder adduction B) Scapular winging C) Loss of arm abduction beyond 15° D) Sensory loss over the lateral forearm Answer: B) Scapular winging Explanation: The long thoracic nerve (C5-C7) supplies the serratus anterior muscle. Injury to this nerve results in scapular winging, where the medial border of the scapula protrudes, especially when the patient pushes against a wall. This can occur during breast cancer surgery or axillary lymph node dissection.
