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 muscle is inseed into the floor of the inteubercular sulcus ? 
Select and explain. 
A. Lattissimus dorsi, B. Teres major, C. Long head of biceps, D. Deltoid
A: Lattissimus dorsi
Answer: A: Lattissimus dorsi 
Explanation: Lattissimus dorsi is inseed into the floor of the inteubercular sulcus Inteubercular sulcus lies between the greater and lesser tubercles. Ref: Gray's Anatomy The Anatomical Basics of Clinical Practice 41 e pg 806.