& D a g g e r ; At least two German-English medical dictionaries incorrectly translate this term as abdominal pressure. Valsalva1 concerned himself with the ear. In his de Aure Humana Tractatus, in 1704, he told how secretions in the middle ear could be forced into the external canal by blowing with the mouth closed while holding the nose. Otologists still recognize this as a procedure for inflating the middle ear. Today, books on physiology, bypassiryg the ear, describe the Valsalva maneuver as attempted forced expiration against a closed glottis. This is less than a complete statement, for the cricopharyngeus muscle also contracts, closing the pharyngoesophageal orifice; the other body cavity sphincters, already closed, close even more tightly during the maneuver.In the physiologic laboratory and in the diagnostic clinic, the maneuver is used in the study and evaluation of the circulatory system. When the intrathoracic pressure rises above the venous pressure in the thoracic veins, the veins collapse and no longer feed blood to the heart for normal cardiac output. This increased intrathoracic pressuresure has still another effect on the veins which will be discussed later.Aside from the voluntarily induced maneuver, we unconsciously carry out a Valsalva maneuver many times a day. Increasing the pressure in the body cavities normally is concerned either with expelling something from these cavities or with stabilizing the trunk, making it a support for the boomlike upper extremity in lifting and pushing.These two functions of the Valsalva maneuver can be referred to as visceral and muscular. In general, the visceral function has either a thoracic or an abdominal focus. The German language anatomist uses the term Bauchpresse (abdominal press t) to indicate the muscles that compress the abdomen. These muscles are the three layers of the abdominal wall with their anterior and posterior aponeuroses. Add to these the diaphragm and the pelvic diaphragm. The pair of rectus muscles may be included. To complete the picture, there is the supporting bony framework, the vertebral column behind, the upper interrupted ring of ribs and the lower ring of the bony pelvis. With these supports the flat muscles form a large, elastic, contractile, inverted, bulblike structure. This abdominal press can be used independently. In some persons, as will be shown, it must be used independently. Generally the abdominal press is reinforced by the thoracic press. In compressing the abdomen the diaphragm and the abdominal wall muscles are synergists. In forced respiration they are antagonists. When for any reason straining is necessary, the relatively weak single layered diaphragm is backed up by the positive head of air pressure produced by the thoracic press. . This brings us to the larynx. I ask students, &dquo;What is the function of the larynx?&dquo; The usual answer is, &dquo;To produce the voice.&dquo; At this point I quote Negus2, who has painstakingly studied the comparative anatomy of the larynx. He has shown that there are many anim...