The meridian originates in the heart itself and divides into three internal branches: one descends towards the small intestine, another rises along the throat to the eye, the third crosses the lung and surfaces in the armpit. There the superficial pathway begins, descending the inner aspect of the arm, following the ulnar border of the forearm, crossing the wrist at the crease, travelling over the palm and ending at the inner nail corner of the little finger.
The Heart governs Blood and commands the vessels: the vigour of circulation and the colour of the complexion depend on it. It houses the Shen, which makes it the reference organ for insomnia, anxiety, memory problems and agitation. It opens into the tongue, manifests in the face, and sweat is its associated fluid. Excessive joy, in the sense of scattering excitement, is the emotion that disturbs it. Its points are among the most used to calm the spirit.