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
Floor of Petit triangle is formed by? 
Select and explain. 
A. Sacrospinalis, B. Internal oblique, C. Rectus abdominis, D. Fascia Transversalis
B: Internal oblique
Answer: B: Internal oblique 
Explanation: Ans. is 'b' i.e., Internal oblique Boundaries of Petit triangle (inferior lumbar triangle) are?Base - Iliac crestAnterior boundary (abdominal boundary) - Posterior border of external oblique muscle.Posterior boundary (lumbar boundary) - Anterior border of latissimus dorsi.Floor is formed by internal oblique muscle.