Final answer:
The inward movement of the chest wall under the sternum during inspiration is known as retractions and is a sign of respiratory distress in newborns, requiring intervention. Other signs of respiratory distress include tachypnea, grunting, and cyanosis.
Step-by-step explanation:
The movement of the chest wall under the sternum moving inward during inspiration is known as retractions and is a sign of respiratory distress in newborns, requiring intervention. This occurs due to the contraction of the external intercostal muscles, which compresses the rib cage. Retractions can be observed as visible indrawing of the tissues between the ribs or in the spaces above the collarbones.
Examples of other signs of respiratory distress in newborns include tachypnea (rapid breathing), grunting (a sound made during exhalation to help keep the lungs open), and cyanosis (bluish discoloration of the skin and mucous membranes due to low oxygen levels).
In cases of respiratory distress, medical intervention is necessary to ensure the newborn receives proper oxygenation and support.