This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Brachial Plexus Injuries, Subject name: Orthopaedics
Winging of scapula is seen in paralysis of which muscle- 
Select and explain. 
A. Serratus anterior, B. Supraspinatus, C. Pectoralis major, D. Infraspinatus
A: Serratus anterior
Answer: A: Serratus anterior 
Explanation: Ans. is 'a' i.e., Serratus anterior Winging of scapulao In this condition the vertebral border of scapula becomes more prominent when patient tries to push against wall.o It occurs in paralysis of the serratus anterior muscle in long thoracic nerve palsy.