Final answer:
The ribs that may be removed during surgery involving a lumbar or simple flank incision for access to the kidney or ureter are the 11th and 12th ribs. These ribs protect the upper portions of the kidneys, which are located at the T12 to L3 vertebral levels.
Step-by-step explanation:
In ureter or kidney surgery involving a lumbar or simple flank incision, the ribs that may need to be removed to provide access to these organs are the 11th and 12th ribs. This is because the upper portions of the kidneys are located at the T12 to L3 vertebral levels and are somewhat protected by the eleventh and twelfth ribs. The removal of ribs for surgical access is carefully considered and is dependent on the specific surgical approach and the individual patient's anatomy. The right kidney is positioned slightly lower than the left due to the presence of the liver, causing some asymmetry within the abdominal cavity. However, even with this asymmetry, the 11th and 12th ribs are the ones associated with kidney protection and potential removal during flank incisions for kidney or ureter surgery.