Heart

The heart is given to the Sun in the western scheme of planetary rulership of the organs, on the analogy of the Sun as the centre and source of the cosmos to the heart as the centre and source of the body. That analogy is older than astrology and is found in Greek medical and philosophical writing; Aristotle made the heart rather than the brain the seat of sensation and of the vital principle, against the Hippocratic and later Galenic view. The atlas also records a wholly separate scheme, the Chinese one, in which the heart, xin, is the ruler among the zang organs, the seat of the shen or spirit and of consciousness, and belongs to the fire phase. The two schemes reached the same organ by different routes and are not translations of one another; they should not be merged.

Ayurvedic medicine gives the heart a further, independent scheme: it is the seat of Sadhaka Pitta, the subtype of pitta dosha that governs emotional processing and the pursuit of one's goals, and of Vyana Vata, the vata subtype that governs circulation and the pulse through the whole body; the classical text Charaka Samhita treats the heart as one of the three vital organs (marma), alongside the head and the bladder region, whose serious injury is described as immediately fatal. Egyptian mortuary practice singled the heart out for a different reason: unlike the other organs, it was left inside the mummified body, since it alone, weighed in the afterlife against the feather of Ma'at in the Book of the Dead's Weighing of the Heart, was needed for judgement.

Sources Christian AstrologyWilliam Lilly with The Roots of Ayurveda: Selections from Sanskrit Medical WritingsDominik Wujastyk

Chinese medicine organises the organs into five zang, the solid or storing organs, heart, lung, spleen, liver and kidney, and six fu, the hollow or transmitting organs, gall bladder, stomach, small intestine, large intestine, bladder and the san jiao or triple burner, which has no anatomical referent at all. Each zang is paired with a fu and with one of the five phases, and each carries functions that do not map onto the organ of western anatomy: the Chinese spleen governs transformation of food and the holding of blood in the vessels, the liver governs the smooth flow of qi and the emotions, and the kidney stores the jing or essence and governs the bones and the will. Paul Unschuld has argued at length that these are systematic correspondences within a coherent theoretical scheme rather than descriptions of anatomy, and that translating them with western organ names is itself a source of confusion.