The three types of ribs are true ribs, false ribs, and floating ribs, categorized by how they connect to the sternum (breastbone).
Here's a breakdown of each type:
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True Ribs (Vertebrosternal): These are the first seven pairs of ribs (1-7). They are called "true" because they have their own costal cartilage that directly attaches to the sternum. This direct connection provides a solid anchor for these ribs.
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False Ribs (Vertebrochondral): These are the next five pairs of ribs (8-12). They are termed "false" because their costal cartilage does not directly attach to the sternum. Instead, the cartilages of ribs 8-10 fuse together and then attach to the costal cartilage of rib 7, indirectly connecting to the sternum.
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Floating Ribs (Vertebral, Free): These are the last two pairs of ribs (11-12). They are also classified as "false" ribs, but are specifically called "floating" because they do not attach to the sternum at all. They only connect to the vertebrae in the back. Their anterior ends are free within the abdominal musculature, offering more flexibility.
| Rib Type | Rib Numbers | Attachment to Sternum |
|---|---|---|
| True Ribs | 1-7 | Direct attachment via their own costal cartilage |
| False Ribs | 8-12 | Indirect attachment (8-10 via rib 7's cartilage) or no attachment (11-12 floating) |
| Floating Ribs | 11-12 | No attachment; free-ending within abdominal muscles |
