What visible sign may indicate inadequate breathing in an infant or child?

Visible use of chest and neck muscles is a sign that indicates inadequate breathing in an infant or child. When a child is struggling to breathe, they may engage accessory muscles in their neck and chest to help draw air into their lungs, which are not typically used during normal, effortless breathing. This use of additional muscles is often observed as retractions, where the skin around the ribs, collarbone, or neck appears to sink in during inhalation.

The other options do not indicate insufficient breathing. Clear speech is usually a sign of adequate air exchange and respiratory function, as it requires a sufficient flow of air through the vocal cords. Normal skin color implies that oxygenation levels are stable; cyanosis or pallor would suggest respiratory distress. Calm behavior generally indicates that the child is not in distress and is breathing adequately, as anxiety or agitation often accompanies inadequate oxygenation.