Thorax: The area of the body that is located between the abdomen and the neck. Within the thorax are the lungs, the heart, and the first section of the aorta. Also known as chest. From Healthy Resources Mucus Relief: Find the Right SolutionBMI Calculator: What Your Numbers MeanWhere Are the Germs Hiding? Featured Centers What Are the Best PsA Treatments for You?Understanding Biologics 10 Things People With Depression Wish You Knew