The rib cage is part of the axial skeleton. The average human is born with the same number of ribs regardless of gender. The ribs articulate with the thoracic vertebra. For example, the first rib ...

In fish, the pelvic fins bear no weight and the pelvic girdle is not attached to the axial skeleton. In amphibians, the pelvic girdle is attached to one vertebra. In the early reptiles, the pelvic ...