Tracheoesophageal fistula: developmental anomaly characterized by an abnormal connection between the trachea and the esophagus; usually accompanies esophageal
atresia, in which the esophagus is closed off at some point

Esophageal atresia: occurs in about 1 of 4,000 live births; approximately one-third of these neonates born prematurely

Numerous anatomic variations, most commonly, esophageal atresia with fistula to the distal segment (see Types of tracheoesophageal anomalies, page 230)