Which is protected by the ribs, sternum and spine?

The ribs, sternum and the spine protect the Heart, lungs, and blood vessels.
The heart, lungs and certain blood vessels are located in the thoracic cavity where the ribs, sternum and spine are located. These skeletal structures serve as a form protection for these delicate and vital organs of the thoracic cavity.

The kidney is partially covered by the kidney by the posterior part of the ribs.

The bladder and urethra are not protected by the skeletal structures listed above.

The Small intestine and the large intestines are structures in the abdominal cavity, not thoracic cavity and they are not protected by the rib, sternum or spine.