The three Yin meridians of the hand include the Taiyin Lung meridian of the hand, the Shaoyin Heart meridian of the hand, and the Syncopal Pericardium meridian of the hand. The general direction is from the chest and abdomen to the fingertips, but the specific direction varies. 1. The starting point of the Hand Taiyin Lung Meridian is the middle jiao, i.e., the stomach, which leads downward to the large intestine, then turns upward, passes through the mouth of the stomach and the diaphragm, turns at the trachea and throat, and then transverses superficially out of the upper side of the chest, along the anterior edge of the medial side of the upper limbs, passes through the elbows of the hands, and the inches behind the wrists, and then along the edges of the intersection between the fissures of the large fish, and terminates at the radius side of the thumbs, where the branch branches off from the back of the wrists, and terminates at the radius side end of the forefingers, and connects with the large intestine meridian. 2. The Heart Meridian of the Shao-Yin Heart of the Hand has its starting point in the Heart, down to the Small Intestine, up to the pharynx, the eye system (the tissue connecting the back of the eye to the brain), and the Lungs, and from the Lungs it passes shallowly out of the armpits, and circulates along the posterior edge of the medial side of the upper arm, passes through the elbows and the medial side of the forearms, and from the back of the palm at the pea-bone it turns into the inner palm, and terminates at the radial end of the little finger. 3. The starting point of the Hand Syncope Yin Pericardium Meridian is in the middle of the chest, and from the chest to the abdomen, it contacts the San Jiao in turn. The branches of the chest meridian run along the middle of the chest, come out from the hypochondrium to the place of three inches below the axilla, and then run upward to the axillary fossa, along the middle of the medial side of the upper arm, and then into the elbow fossa, and then run down along the forearm between the two tendons, and then enter into the middle of the palm, and then terminate in the middle finger tip, and then the branch meridian will be divided in Laogong, and then terminate at the tip of the ring finger tip. The corresponding acupuncture operation needs to be carried out by a professional doctor, it is not recommended to operate on their own, the patient should consult a doctor in time to identify and treat.