It should cause readers to stop, and wonder: "Why the rib?" While we cannot conclusively answer that question, we can spend a few moments pondering. For instance, did you know that the human body contains one bone, that if removed, has the potential to grow back? This bone just happens to be the lower rib, and if it is removed (leaving the outer-covering intact), the bone can grow back.

This would mean that Adam didn't go through life physically incomplete, or wounded in any way. God truly is the Great Physician.

Genesis 2:21