Objective: We present two infants with holoprosencephaly and clefts of the
primary palate, who developed nasal airway obstruction due to a previously
undocumented cause: a ball-valve-like action of a rudimentary premaxilla, w
hich was extremely mobile on a soft tissue stalk. In such patients, the imp
ortance of intranasal examination to identify a rudimentary premaxilla, in
order to preserve it, and if necessary, surgically stabilize it, is illustr
ated.