This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Umblicial cord and diaphragm, Subject name: Anatomy
Most commonly foreign body lodges in which pa of esophagus 
Select and explain. 
A. At the level of cricopharyngeus, B. Where it crosses the aoic arch, C. Where it is crossed by left bronchus, D. Where it pierces the diaphragm
A: At the level of cricopharyngeus
Answer: A: At the level of cricopharyngeus 
Explanation: There are physiological constrictions in esophagus at 4 levels as mentioned below, foreign body M/C lodges at first constriction. Constriction of oesophagus Veebral Level Distance From Upper Incisors Cricopharyngeal C6 6" Arch of aoa T4 9" Crossing of left bronchus T6 11" Esophageal opening in diaphragm T10 15"