Infants can drink and breathe at the same time because of the way their larynx and hyoid bone are situated. When a baby is born, the larynx, or voicebox, and the hyoid bone are situated higher up in the nasal cavity than in adults, which makes it possible for them to drink and breathe without aspirating, or choking on liquids or foods. As the baby gets older, both the larynx and hyoid bone drop to the adult level, eventually settling about two vertebrae down.
More facts about the larynx:
- Males actually experience two larynx drops in their lives. One occurs when they are infants, and one takes place when they go through puberty. The second larynx drop is what causes males' voices to deepen.
- Infants are often more prone to choking as they get to be about 4 months old because of the way that their swallowing mechanism changes. As the infant's body changes, the larynx becomes less protected, which can make it easier for the baby to aspirate.
- The placement of the larynx and hyoid bone is also why many infants and children are prone to gestroesophageal reflux — basically stomach contents coming back up. In fact, most children who are less than 3 months old have at least one significant reflux episode a day.