Which organ is primarily associated with bones and joints?

The organ primarily associated with bones and joints is the kidney. In traditional Chinese medicine, the kidneys are believed to govern the bones and influence the health of the joints. This association is rooted in the concept that the kidneys store the essence (Jing), which is vital for growth and development, including the health of not only the bones but also the marrow, which is involved in the production of blood and the nourishing of the bones.

Additionally, the kidneys' health is thought to be linked to the balance of Yin and Yang in the body, which indirectly affects the strength and integrity of the skeletal system and joints. For example, a deficiency in kidney energy can lead to conditions like osteoporosis or joint pain, demonstrating their critical role in maintaining bone and joint health.

In contrast, while the lung plays a crucial role in respiration and gas exchange, the spleen is primarily associated with digestion and nourishment of the body's tissues. The heart is vital for circulation and the regulation of blood flow but does not have the direct relationship with bones and joints as the kidneys do.