Bronchoaortic constriction

The bronchoaortic constriction is the thoracic narrowing of the esophagus that is produced by the combined compression of the esophagus by the arch of the aorta and the left main bronchus.

As the thoracic esophagus descends through the superior mediastinum, it first passes behind the arch of the aorta at approximately T4 level, where it is indented by the aortic arch (aortic constriction). A short distance below, at about the level of T5, it is crossed anteriorly by the left main bronchus, producing a second narrowing (bronchial constriction). Because these two constrictions occur very close together, they are often collectively referred to as the bronchoaortic constriction.

Clinical correlates

• The bronchoaortic constriction is located approximately 25-27 cm from the upper incisor teeth during endoscopy. It represents one of the four normal anatomical constrictions of the esophagus and is a common site where swallowed foreign bodies may become lodged. It is also a frequent location for corrosive injuries, esophageal strictures, and carcinoma.

• Clinically, enlargement of adjacent structures, such as an aortic aneurysm, dilatation of the aortic arch, enlarged tracheobronchial lymph nodes, or pathology of the left main bronchus, may further compress the esophagus at this level and produce dysphagia.

• During radiological examinations using a barium swallow, the bronchoaortic constriction appears as a characteristic indentation on the esophageal shadow and serves as an important anatomical landmark.