The thorax encloses the lungs, the heart, the oesfagus, and the major thoracic vessels.
The skeleton consists of 12 thoracic vertebrae, 12 pairs of ribs and the sternum. Together they shape the thorax and give protection to the intrathoracic tissues/organs.
The diaphragm separates the thoracic cavity from the abdominal cavity.
To open class X-thorax, just click on the right side of the screen on X-thorax under the section Techniques.