Narrowest part of esophagus is at?: (A) Cricopharyngeal sphincter, (B) At the Aortic constriction, (C) At the crossing of left principal bronchus, (D) At the diaphragmatic opening
Answer is A. Ans. is 'a' i.e., Cricopharyngeal sphincter * The narrowest part of esophagus is its commencement at the cricopharyngeal sphincter.