Anatomy of the vocal apparatus

Functioning of the lungs and diaphragm.

To master public speaking, it is essential to understand the biological engineering that underlies the voice.

The phonatory apparatus is not limited to the throat; it is a complex pneumatic system where the prime mover is the diaphragm.

This muscle, shaped like a parachute or dome, separates the thoracic cavity from the abdominal cavity and is directly responsible for air management.

When inhaling, the diaphragm contracts and descends, creating a vacuum that allows the lungs to expand downward, maximizing their volume.

On exhalation, the diaphragm relaxes and rises, pushing air into the larynx to produce sound.

A fascinating anatomical and functional aspect is the connection between the diaphragm and the pericardium, the membrane that surrounds the heart. The two are connected by a tendinous center.

This implies that, when taking a deep, diaphragmatic breath, the downward movement of the diaphragm exerts a gentle traction on the pericardium.

This physical phenomenon acts as a mechanical massage on the heart, which facilitates venous return and sends a direct signal to the nervous system to slow the heart rate.

Therefore, anatomical control of this muscle not only improves vocal quality, but is a physiological switch to deactivate stress.

Difference between breathing for living and breathing for speaking

There is a fundamental distinction between vegetative breathing (the one we perform unconsciously to survive) and professional or communicative breathing.

Vital breathing is automatic, rhythmic and generally superficial; its sole purpose is basic gas exchange. However, for public speaking, this breathing is insufficient.

Public speaking requires an active and controlled flow of air, capable of sustaining long sentences without breaks and of projecting the voice to the last row of an auditorium.

If we rely solely on our habitual breathing pattern when speaking, we will encounter premature vocal fatigue and a weak voice.

The "speaker's breath" should be a voluntary and trained act, where the inhalation is quick and quiet, but the exhalation is prolonged and consciously managed to vibrate the vocal cords with the proper pressure.

Turning this conscious process into an unconscious habit is the goal of vocal training.

Summary

The phonatory apparatus is a complex pneumatic system where the diaphragm acts as a prime mover. This muscle regulates the intake and output of air efficiently.

There is a vital connection between the diaphragm and the heart. Deep breathing acts as a physiological switch that massages the heart and reduces stress.

Breathing for speaking requires voluntary and trained control of airflow. It is different from vital breathing, as it seeks to sustain long sentences without vocal fatigue.