A 4-month-old boy is brought to the physician for a 2-month history of recurrent stridor. It is not mitigated with extension of the neck or with prone or upright positioning. There is no family history of similar conditions. Growth parameters and vitals are unremarkable. Which of the following is the most likely explanation for these findings?
Adenoid hypertrophy
Infection
Laryngomalacia
Tracheomalacia
Vascular ring
