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What is 2nd constriction of esophagus is caused by - and explain in detail?
Ans. is 'b' i.e., Arch of aorta o 2nd constriction is at T4 level where arch of aorta crosses esophagus. Esophageal constrictionsNumberDistance from incisorBony levelAnatomical landmark1st15 cm (6 inches)C6At its beginning (pharyngo-esophageal junction)2nd22[?]5 cm (9 inches)T4Crossing of aortic arch3rd27[?]5 cm (11 inches)T6Crossing of left main bronchus4th37[?]5 - 40 cm (15-16 inches)T10Piercing diaphragm (at lower esophageal sphinctor)