To cancel the lower-frequency portions of the noise, noise-cancelling headphones use active noise control. They incorporate a microphone that measures ambient sound, generate a waveform that is the exact negative of the ambient sound, and mix it with any audio signal the listener desires.
Esophageal hiatus. In human anatomy, the esophageal hiatus is an opening in the diaphragm through which the esophagus and the vagus nerve pass. It is located in the right crus, one of the two tendinous structures that connect the diaphragm to the spine. Fibers of the right crus cross one another below the hiatus.
Esophageal manometry (muh-NOM-uh-tree) is a test that shows whether your esophagus is working properly. The esophagus is a long, muscular tube that connects your throat to your stomach. Esophageal manometry measures the rhythmic muscle contractions that occur in your esophagus when you swallow.Esophageal manometry also measures the coordination and force exerted by the muscles of your esophagus.During esophageal manometry, a thin, flexible tube (catheter) that contains sensors is passed through your nose, down your esophagus and into your stomach.Esophageal manometry can be helpful in diagnosing certain disorders that may affect your esophagus.uring esophageal manometry, a thin, flexible tube (catheter) that contains sensors is passed through your nose, down your esophagus and into your stomach. Esophageal manometry can be helpful in diagnosing certain disorders that may affect your esophagus.