Ribs

Joe Muscolino

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    • There are 12 pairs of ribs, left and right, for a total of 24 ribs.
    • All ribs articulate with the spine posteriorly.
    • Most pairs of ribs articulate with the sternum anteriorly.
    • Ribs articulate with the sternum via cartilage called a costal cartilage (costal means rib).
      • If a rib articulates directly with the sternum with its own costal cartilage, it is called a true rib.
      • If a rib does not have its own articulation with the sternum, but instead joins the costal cartilage of another rib, it is called a false rib.
      • If a rib does not articulate at all with the sternum, it is called a floating rib (floating ribs are also false).
    • Ribs protect the contents within the thoracic cavity (heart, lungs, and major vessels).

     

    NOTES:

    1. There are seven pairs of true ribs and five pairs of false ribs, of which two of the pairs of false ribs are floating false ribs.
    2. Ribs #1-7 are true ribs
    3. Ribs #8-12 are false ribs because they join into the costal cartilage of rib #7.
    4. Ribs #11-12 are false floating ribs because they do not articulate with the sternum at all (they are usually described simply as floating ribs).
    Superior view of ribs #1-12, from top left to bottom right. Note the changes in the sizes of ribs.

    Superior view of ribs #1-12, from top left to bottom right. Note the changes in the sizes of ribs.

     

    Posterior view of a "typical rib."

    Posterior view of a “typical rib.”

     

    Medial view of a "typical rib."

    Medial view of a “typical rib.”

     

    Anterior view of the bony thorax.

    Anterior view of the bony thorax.