This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Upper limb, Subject name: Anatomy
What is the action of anterior fibres of deltoid? 
Select and explain. 
A. Flexion, B. Lateral Rotation, C. Flexion and medial dotation, D. Extension and lateral rotation
C: Flexion and medial dotation
Answer: C: Flexion and medial dotation 
Explanation: Multipennate acromial fibres are powerful abductors of arm at the shoulder joint from beginning to 90deg.Extension and lateral rotation of arm is mediated by the posterior fibres.Flexion and medial rotation is mediated by the anterior fibres.B D Chaurasia 7th edition Page no: 70,71