Rib cage
The rib cage is the arrangement of ribs attached to the vertebral column and sternum in the thorax of most vertebrates, that encloses and protects the heart and lungs. In humans, the rib cage, also known as the thoracic cage, is a bony and cartilaginous structure which surrounds the thoracic cavity and supports the shoulder girdle to form the core part of the human skeleton. A typical human rib cage consists of 24 ribs in 12 pairs, the sternum and xiphoid process, the costal cartilages, and the 12 thoracic vertebrae.
Ziony Zevit
In an article published in 2001, Scott F. Gilbert and Zevit argue that the Bible might be interpreted that Eve was not made from Adam’s rib, but his baculum; which would explain why humans don't have one. Zevit's article published in "Biblical Archaeology Review" in 2015 presents the same theory and attracted certain public attention.