Joint tuberculosis (Flowing Phlegm) refers to a chronic suppurative disease occurring between the bone and joint. It is believed in Chinese medicine that this disease is mostly related to prenatal insufficiency, or postnatal kidney deficiency, which leads to emptiness in the bones for pathogenic wind, cold and turbid phlegm to take the advantage to enter and gather in the bones. Its clinical feature is neither red nor hot in the initial stage. The tumefaction and pain are not obvious and suppuration is also slow. Mter rupture of ulceration, the pus discharged is in thin nature, mixed with bad  cottonlike substance, and the wound is difficult to heal and can form a sinus, which can damage the bones and marrow to result in deformity and even endanger the life.

Due to difference in the pathogenic positions, there can be different terms. For instance, flowing phlegm occurring on the back is termed "Turtle Shell Phlegm". Flowing phlegm occurring at the two sides of the lumbar vertebrae is termed "Deficient Phlegm of Shenshu (BL 23)'. Flowing phlegm occurring in the hip joint is termed "Huantao(GB 30) Phlegm", and flowing phlegm happening in the knee is termed "Heding(Extra) Phlegm". It is similar to bone and joint tuberculosis.