the data obtained from fiber esophagoscopy of patients and electromyography of the pharynx-esophagus junction of dogs have shown that the upper ( cranial ) esophageal sphincter control food passage from the pharynx to the esophagus and prevents food reflux to the laryngopharynx , protecting airways from aspiration .
C0014873
esophagoscopy
C0014876
esophagus