Which structure is NOT mentioned as being less prominent in infants than in adults?

The epiglottis is a structure that plays a crucial role in protecting the airway during swallowing. In infants, the epiglottis is more flexible and positioned in such a way that it covers the trachea during feeding, which is essential to prevent aspiration. However, its prominence does not significantly decrease compared to adults, as its role in the swallowing mechanism remains vital even in infancy.

In contrast, the thyroid notch, cricoid cartilage, and thyroid cartilage have structural characteristics that are indeed less prominent or developed in infants relative to adults. For instance, the thyroid notch is less defined in infants due to their developing laryngeal structure. The cricoid cartilage is smaller and more rounded in infants, and the thyroid cartilage, which is significant for adult pitch modulation, does not have the same prominence in infants. Therefore, the epiglottis is the correct answer as it is not characterized by reduced prominence in infants compared to adults.