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.
Medical Definition of DEAD SPACE. 1. : space in the respiratory system in which air does not undergo significant gaseous exchangeâsee anatomical dead space, physiological dead space. 2.: a space (as that in the chest following excision of a lung) left in the body as the result of a surgical procedure.efinition of DEAD SPACE. : the portion of the respiratory system which is external to the bronchioles and through which air must pass to reach the bronchioles and alveoli. ADVERTISEMENT. noun.