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.
MOST MAJOR HALF MARATHONS ARE FOR RUNNERS--but walkers can do them too. One advantage of a half marathon over a full marathon is that you won't need to spend as much time on the course. Most reasonably fit individuals should be able to walk 13.1 miles in around four hours.