LESSON 3
TREATING CHEST INJURIES
Section I. GENERAL
3-1.
THORACIC CAVITY
The chest is also called the thorax. The thoracic (chest) cavity is the body
cavity located between the neck and the diaphragm. It is surrounded by the rib cage
(figure 3-1). The thoracic cavity contains the lungs, the heart, and many major blood
vessels. Any injury to the chest can be serious. A penetrating object, for example,
can puncture a lung, an artery or vein, or the heart itself.
3-2.
RIB CAGE
The rib cage includes the ribs, the 12 thoracic vertebrae (spine), and sternum
(breastbone). The ribs are connected to the vertebrae in back and all but four ribs (the
lowest two pairs) are connected to the sternum in front by cartilage. The small spear-
like structure at the bottom of the sternum is the xiphoid process. Damage to the rib
cage can interfere with breathing since the movement of the rib cage assists in
inhalation and exhalation. (See Subcourse MD0532, Cardiopulmonary Resuscitation,
for additional information on the mechanics of respiration.)
Figure 3-1. Rib cage (showing location of heart).
MD0554
3-2