Pinna embryology

The auricle or pinna is formed from the fusion of six raised soft tissue swellings (hillocks) on the surface of the embryo. Three of these hillocks are derived from the first branchial arch (FBA) and three from the second branchial arch (SBA) during the fifth and sixth weeks of intrauterine life. The hillocks of the FBA and SBA flank the first branchial cleft (FBC). The FBA and SBA contribute almost equally to the immature pinna, whereas the mature pinna predominantly originates from the SBA.