Since the concept of being below is itself somewhat vague, scientists define the nadir in more rigorous terms. Specifically, in astronomy, geophysics and related sciences (e.g., meteorology), the nadir at a given point is the local vertical direction pointing in the direction of the force of gravity at that location.
anatomical dead space. In pulmonary physiology, the area in the trachea, bronchi, and air passages containing air that does not reach the alveoli during inspiration and is not involved in gas exchange. This is termed dead space because the air does not reach the alveoli and is not involved in gas exchange. Normal anatomical dead space is 2.2 ml/kg or 1 ml/lb.
In order to describe body parts and positions correctly, the medical community has developed a set of anatomical positions and directional terms widely used in the healthcare industry. The anatomical reference point is a standard body position called the anatomical position. In the anatomical position, the body is erect, the palms of the hand face forward, the thumbs point away from the body, and the feet are slightly apart. Itâs important to understand the anatomical position because most directional terms are based off it.