FIGURE 1-11 Body Cavities. (a) The dorsal body cavity is bounded by the bones of the skull and vertebral column. The muscular diaphragm divides the ventral body cavity into a superior thoracic (chest) cavity and an inferior abdominopelvic cavity.he Thoracic Cavity The walls of the thoracic cavity surround the lungs and heart; associated organs of the respiratory, cardiovascular, and lymphatic systems; the inferior portions of the esophagus; and the thymus.
Half marathon. A half marathon is a road running event of 21.0975 kilometres (13.1094 mi) â half the distance of a marathon. Participation in half marathons has grown steadily since 2003, partly due to the fact that it is a challenging distance, but does not require the same level of training that a marathon does.
If this is something you did before you were a runner, then now's a good time to stop that habit. A marathon, by definition, is a 26.2 mile race. So only races that are 26.2 miles should be called marathons. A half marathon race is 13.1 miles. Other races are also named by their distances, such as a 5K race (3.1 miles) and a 10K race (6.2 miles).