What nerves are primarily associated with the innervation of the kidney?

The lesser and least splanchnic nerves are primarily involved in the innervation of the kidneys, as they originate from the thoracic sympathetic trunk. These nerves carry sympathetic fibers that play a crucial role in the autonomic regulation of renal function, including blood flow to the kidneys and the regulation of glomerular filtration. The sympathetic innervation provided by these splanchnic nerves helps modulate renal activity in response to various physiological conditions.

On the other hand, the right phrenic nerve primarily innervates the diaphragm and does not have a significant role in renal innervation. The mediastinal nerve, while involved in thoracic innervation, does not directly affect the kidneys. The pelvic splanchnic nerve, primarily responsible for parasympathetic innervation, is more concerned with pelvic organs rather than the kidneys, which are regulated more by sympathetic pathways. Thus, the significant sympathetic innervation provided by the lesser and least splanchnic nerves is what makes them the correct answer in relation to the kidney's innervation.