Acupuncture is one of the oldest, most commonly used medical procedures in the world. Originating in China more than 2,000 years ago, acupuncture became widely known in the United States in 1971. Traditional Chinese Medicine theorizes that the more than 2,000 acupuncture points on the human body connect with 12 main and 8 secondary pathways, called meridians. Chinese medicine practitioners believe these acupuncture meridians conduct energy, or Qi (pronounced "chee") , between the surface of the body and internal organs. Acupuncture promotes the natural flow of Qi which regulates spiritual, emotional, mental, and physical balance. Qi is influenced by the opposing forces of yin and yang. According to traditional Chinese medicine when yin and yang are balanced they work together with the natural flow of Qi to help the body achieve and maintain health. Acupuncture is believed to balance yin and yang, keep the normal flow of energy unblocked, and restore health to the body and mind. Traditional Chinese medicine practices (including acupuncture, herbs, diet, massage, and meditative physical exercises) all are intended to improve the flow of Qi.