The thoracic cage, or rib cage, forms the bony and cartilaginous framework of the chest. It protects important organs and provides landmarks for identifying ribs. This lesson explains the sternum, the parts and articulations of a typical rib, and the groups into which ribs are classified.
The thoracic cage consists of 12 pairs of ribs, their costal cartilages, and the sternum. Posteriorly, the ribs are anchored to the 12 thoracic vertebrae, T1–T12. The cage forms the framework of the thorax and helps protect the heart and lungs.
All flashcards
What is the thoracic cage, and what is one of its main functions?
It is the framework formed by the sternum, 12 pairs of ribs, and costal cartilages. It helps protect the heart and lungs.
What are the three parts of the sternum?
The manubrium is the superior portion, the body is the elongated central portion, and the xiphoid process is the inferior tip.
How does the sternal angle help in rib identification?
The sternal angle is where the manubrium meets the body of the sternum. The second rib attaches there, providing a palpable starting point for counting ribs.
What is the difference between the head and tubercle of a typical rib?
The head articulates with costal facets on vertebral bodies, primarily the corresponding vertebra. The tubercle articulates with a facet on the transverse process of the corresponding vertebra.
How are true, false, and floating ribs distinguished?
True ribs 1–7 attach directly to the sternum through their costal cartilages. False ribs 8–12 do not attach directly; ribs 11–12 are floating ribs whose cartilages end in the lateral abdominal wall musculature.
Quiz questions
Which structures make up the thoracic cage?Answer: The sternum, 12 pairs of ribs, and their costal cartilages.
What are the three parts of the sternum?Answer: The manubrium, body, and xiphoid process.
Why is the sternal angle useful when identifying ribs?Answer: It marks the second rib, a palpable starting point for counting.
Which feature of a typical rib articulates with the transverse process of its corresponding vertebra?Answer: The tubercle.
A rib’s cartilage joins the cartilage of the rib immediately above it. Which group includes this rib?Answer: False ribs 8–10, which connect indirectly through adjacent cartilages.
Based on Anatomy and Physiology 2e by J. Gordon Betts, Kelly A. Young, James A. Wise, Eddie Johnson, Brandon Poe, Dean H. Kruse, Oksana Korol, Jody E. Johnson, Mark Womble, Peter DeSaix (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.