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
Human body temperature change according to activities and external factors. In addition to varying throughout the day, normal body temperature may also differ as much as from one day to the next, so that the highest or lowest temperatures on one day will not always exactly match the highest or lowest temperatures on the next day. Normal human body temperature varies slightly from person to person and by the time of day. Consequently, each type of measurement has a range of normal temperatures. The range for normal human body temperatures, taken orally, is (). This means that any oral temperature between is likely