Ribs 11 and 12 are called floating ribs because they_______.

The correct option is C

Attached only to the vertebral column and have no connection to the sternum.

The first rib attaches to the sternum anteriorly and to the T1 vertebra posteriorly. The next few ribs articulates similarly until we reach the eight rib. The eighth, ninth, and tenth rib articulate with the costal cartilages of the ribs above them instead of the sternum. The eleventh and twelfth don’t have any articulations anteriorly and are free. Their only attachment is posteriorly, to the eleventh and twelfth thoracic ribs. As these ribs aren't fixed anteriorly, they seem to float and are called floating ribs.