The thorax is the part of the body that lies between the head and the abdomen. It contains the organs heart and lungs. The ribcage protects the vital organs of the thorax.
The thorax (thorax, 'breastplate, cuirass, corslet') is a division of an animal's body that lies between the head and the abdomen. In mammals, the thorax is the region of the body formed by the sternum, the thoracic vertebrae, and the ribs. It extends from the neck to the diaphragm, and does not include the upper limbs. The heart and the lungs reside in the thoracic cavity, as well as many blood vessels. The inner organs are protected by the rib cage and the sternum. In insects and the extinct trilobites, the thorax is one of the three main divisions (or tagmata) of the creature's body, each of which is in turn composed of multiple segments. It is the area where the wings and legs attach in insects, or an area of multiple articulating plates in trilobites. In most insects, the thorax itself is composed of three segments; the prothorax, the mesothorax, and the metathorax.
Contributions by IronChris, Bensaccount, and Tristanb.