Trachea front and sides of the trachea to protect and maintain the airway. In front of the rings lies connective tissue and skin. Several other structures pass or sit over it; the jugular arch, which joins the two anterior jugular veins, sits in front of the upper part of the trachea. The sternohyoid and sternothyroid muscles stretch along its length, and the thyroid gland sits below this; with the isthmus of the gland overlying the second to fourth rings. The first tracheal ring is broader than the rest, and often divided at one end; it is connected by the cricotracheal ligament
Traditional Chinese medicines derived from the human body parts of the human body should be used as drugs, such as bone, flesh, and gall. This is really very rude and inhuman. In the present category, all parts of the human body that have been used as drugs are recorded. The use of drugs from the human body that is not contrary to morality is recorded in detail. Those drugs that are cruel or foul [慘忍邪穢] are not recorded in detail. But all of them are listed in this category. (tr. Luo 2003: 4133) Li does not give prescriptions for 12 of the 35 human drugs, which he considered