Quiz 3: The Thorax
D Explanation: Thorax. The thorax, or chest region, is a hollow body cavity enclosed by a thoracic bony and muscular wall. The skeleton of the thorax consists of (1) a midline sternum, (2) 12 pairs of ribs and associated costal cartilages, and (3) 12 vertebrae.
B Explanation: Ribs to sternum. The typical rib is joined to the sternum by its own costal cartilage. The manubrium is a portion of the sternum.
C Explanation: True, false, and floating. There are three types of ribs: true (ribs 1-7), false (ribs 8-10), and floating (ribs 10-12).