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.
Between training runs and official races, I have run a half marathon distance more than 50 times. The 13.1-miles was daunting at first, but it quickly became my favorite distance. Hereâs how to train for your first half marathon. To the average person, running 13 miles sounds crazy. It takes about two hours on average to finish if you are in good shape and you could spend months preparing for your first race. Hereâs the good news: half marathons are not that hard. In fact, they are considerably easier than a full marathon at 26.2 miles.