Figure 2: "Alphabet P sign" formed by acoustic shadow of hyoid bone (HY), swollen epiglottis (pointed by white arrows). From Hung TY et al. Am J Emerg Med. 2011; 29:359.e1-3. Epub 2010 Aug 1

et al. Am J Emerg Med. 2011; 29:359.e1-3. Epub 2010 Aug 1">