The meridian originates in the centre of the chest, reaches the pericardium, crosses the diaphragm and travels through the three burners. A superficial branch emerges from the chest one hand-width lateral to the nipple, rises towards the armpit, then descends the front of the arm between the Lung and Heart meridians. It crosses the elbow crease, follows the forearm between the two tendons, crosses the wrist, travels over the centre of the palm and ends at the tip of the middle finger.
The Pericardium protects the Heart and receives external attacks in its place, particularly heat. It governs Blood and influences circulation in the chest, hence its use in oppression and chest pain. It houses and calms the Shen, which makes it, together with the Heart, the reference meridian for anxiety and insomnia. Its pathway along the arm explains its action on elbow and wrist pain, and its point Neiguan is recognised against nausea and motion sickness.