The adult sternum consists of three parts: manubrium, body, and xiphoid process (see Fig. 4.1). Prenatally, it consists of six main parts. The first and last parts remain distinguishable as the manubrium and xiphoid process, respectively.
The middle four parts (sternebrae) fuse to form the body. The three main parts were named after the resemblance of the sternum to the short sword favored by Roman troops and gladiators—thus, the manubrium(= handle), the body (in older terminology = gladiolus = small sword), and the xiphoid process (= sword point).
Figure 4.1 A. Anterior view of the sternum. B. Sternum, ribs, and costal cartilages forming the thoracic skeleton.
Figure 4.4 Fifth right rib as it articulates with the vertebral column posteriorly and the sternum anteriorly. Note that the rib head articulates with the vertebral body of its own number and that of the vertebra immediately above. Note also the presence of the costal groove along the inferior border of the rib.