This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
Inseion of pectoralis major is at: 
Select and explain. 
A. Lateral lip of bicipital groove of humerus, B. Medial lip of bicipital groove of humerus, C. In the bicipital groove of humerus, D. Clavicle
A: Lateral lip of bicipital groove of humerus
Answer: A: Lateral lip of bicipital groove of humerus 
Explanation: Pectoralis major arises from the anterior surface of the sternal half of the clavicle; from breadth of the half of the anterior surface of the sternum, as low down as the attachment of the cailage of the sixth or seventh rib; from the cailages of all the true ribs, with the exception, frequently, of the first or seventh and from the aponeurosis of the abdominal external oblique muscle. From this extensive origin the fibers converge in a flat tendon, about 5 cm in breadth, which is inseed into the lateral lip of the bicipital groove of the humerus.