Sanjiao, Triple Warmer, or Triple Burner is one of the Yang systems (Fu) that is not connected to a physical organ recognized by Western medicine. Like all the systems in Chinese medicine, it is a functional system. In other words, it is represented by a group of functions.
The Triple Warmer meridian originates at the tip of the ring finger, up the arm and shoulder and down to the chest cavity. It then branches down the thigh and the knee, with the other branch going up to the ear, circling the face and meeting the Gall Bladder meridian.
The Triple Warmer, as the name implies, consists of 3 parts. The upper warmer is related to the Lung and Heart (respiration); the middle warmer with the Stomach, Spleen, Liver and Gall Bladder (digestion and assimilation); and the lower Warmer with Small Intestine, Large Intestine, Kidney and Urinary Bladder (reproduction and elimination).
Overall, the Triple Warmer governs the endocrine system, the autonomic nervous system and appetite regulation.