False ribs
Encyclopedia
The false ribs, are the five sets of ribs below the top seven true ribs
True ribs
The first seven ribs are connected posteriorly with the vertebral column, and anteriorly, through the intervention of the costal cartilages, with the sternum; they are called true ribs or vertebro-sternal ribs....

. A rib is considered to be "false" if it has no direct attachment to the sternum, also known as the breast bone. Of these:
  • the first three (eighth, ninth, and tenth rib) have their cartilages attached to the cartilage of the rib above (vertebro-chondral):
  • the last two (eleventh rib
    Eleventh rib
    The eleventh rib has a single articular facet on the head, which is of rather large size.It has no necks or tubercles, and is pointed at its anterior ends.The eleventh has a slight angle and a shallow costal groove....

     and twelfth rib
    Twelfth rib
    The twelfth rib has a single articular facet on the head, which is of rather large size. It has no necks or tubercles, and is pointed at its anterior ends....

    ) are free at their anterior extremities and are termed floating ribs or vertebral ribs because they connect neither with the sternum nor with another rib. . These ribs are relatively small and delicate, and are capped by a cartilaginous tip.

Ninth rib

The frontal part of the ninth rib is at the same level as the first lumbar vertebra. This level is called planum transpyloricum, since the pylorus
Pylorus
The pylorus is the region of the stomach that connects to the duodenum . It is divided into two parts:* the pyloric antrum, which connects to the body of the stomach.* the pyloric canal, which connects to the duodenum....

 is also at this level.

Tenth rib

The tenth rib attaches directly to the body of vertebra T10 instead of between vertebrae like the second through ninth ribs. Due to this direct attachment, vertebra T10 has a complete costal facet
Costal facet
Costal facet can refer to:* Superior costal facet* Transverse costal facet* Inferior costal facet...

 on its body. In the Japanese and some other people groups, the tenth rib is also usually a floating rib
Floating rib
Floating ribs are four atypical ribs in the human ribcage. They are called so because they are attached to the vertebrae only, and not to the sternum or cartilage coming off of the sternum. Some people are missing one of the two pairs. Others have a third pair. Most, however, possess only two...

, lacking the cartilaginous connection to the seventh rib.
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