This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thorax, Subject name: Anatomy
Constrictions of the esophagus are present in all sites except 
Select and explain. 
A. At cricopharyngeal junction, B. Crossed by Arch of Aoa, C. Surrounded by Right crus of Diaphram, D. Crossed by left principle bronchus
A: At cricopharyngeal junction
Answer: A: At cricopharyngeal junction 
Explanation: ConstrictionsNormally the esophagus shows 4 constrictions at the following levels.1.At its beginning, 15 cm from the incisor teeth.2.Where it is crossed by the aoic arch, 22.5 cm from the incisor teeth.3.Where it is crossed by the left bronchus, 27.5 cm from the incisor teeth.4.Where it pierces the diaphragm 37.5 cm from the incisor teethRef: BD Chaurasia; Volume 1; 6th edition; Page no: 268