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
Which of the following aeries supply pectoralis major muscle? 
Select and explain. 
A. Pectoral branches of thoracoacromial aery, B. Intercotal aery, C. Lateral thoracic aery, D. Subclan aery
A: Pectoral branches of thoracoacromial aery
Answer: A: Pectoral branches of thoracoacromial aery 
Explanation: PECTORALIS MAJOR:-Origin: Small clavicular head- medial half of anterior aspect of clavicle.Sternocostal head- lateral half of sternum upto 6th cailage., and medial pas of 2nd to 6th costal cailages.Inseion:-U shaped inseion into lateral lip of bicipital groove.Nerve supply:-Lateral pectoral( C5-C7)Medial pectoral (C6-C8, T1)Action:-Clavicular head- flexes arm Sternocostal head-adducts and medially rotates armOnly muscle of upper limb which is supplied by all 5 spinal segments that form brachial plexus.Blood supply:- pectoral branch of thoracoacromial aery {Reference: Vishram Singh, pg no.40}