1. An extreme degree of resonance.
2. Resonance increased above the normal, and often of lower pitch, on percussion of an area of the body; occurs in the chest as a result of overinflation of the lung as in emphysema or pneumothorax and in the abdomen over distended bowel.
The information shown above for hyperresonance is provided by Stedman's.
* Stedman's, part of Lippincott Williams & Wilkins, provide a comprehensive line of health-science publications for healthcare professionals and medical students.