The woman's broken "chest bone" mentioned in this article was undoubtedly her sternum. A rib would never be referred to as a "chest bone", but the sternum quite commonly is. It is certainly not incorrect, though it is informal; the journalist who wrote this report probably thought that some of his readers would not understand the word "sternum". In medical circles the term "chest bone" would not be used, though a doctor might use it to a patient for the reason just mentioned: to avoid technical language.
"Breastbone" is more common as a non-technical alternative to sternum, but plenty of people call it the chest bone.
"The sternum (chest bone) lies in the midline of the anterior chest wall."
http://www.mananatomy.com/body-systems/skeletal-system/stern..."How to protect your chest bone (sternum) after thoracic surgery"
http://tinyurl.com/q8d4733"The sternum can also be called the breastbone or chest bone."
http://www.newhealthguide.org/Sternum-Pain.htmletc., etc.
peer agreement (net): +5