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Britannica Sources used in this answer

How are the ribs connected to the sternum?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
Front and back views of the human skeleton are shown side by side, with labeled bones including the skull, spine, ribs, pelvis, arms, legs, hands, and feet. Insets detail the bones of the foot and hand, highlighting major bone groups and anatomical terms.
human skeleton Front and back views of the human skeleton.

In humans, the connection between the ribs and the sternum varies based on the rib's classification:12

  • True Ribs: The first seven pairs of ribs are attached directly to the sternum by pliable segments of cartilage known as costal cartilages.13
  • False Ribs: The 8th, 9th, and 10th pairs do not join the sternum directly. Instead, their costal cartilages connect to the cartilage of the rib immediately above them.12
  • Floating Ribs: The 11th and 12th pairs are termed floating ribs because they do not reach the front of the body or the sternum at all; their cartilages end within the muscle of the abdominal wall.132

This arrangement allows the rib cage to remain semirigid while providing the flexibility necessary for the chest to expand during breathing.32