File:Devt of external ear.JPG

The development of the Pinna

The image illustrates the development of the pinna.

1 tragus

2 helix

3 cymba concha

4 concha

5 antihelix

6 antitragus

The pinna or auricle develops around the first and second pharyngeal arches as a series of auricular enlargements or hillocks around the 5th week of development. Gradually by the 6th week the hillocks grow in size and increase to six in number, three on the first arch and 3 on the second arch, the first of which starts at the bottom anterior side going in a clockwise direction. In the 7th week the hillocks enlarge further and each of the arches contributes to a specific part of the pinna. The first arch gives rise to the tragus, helix and cymba concha whereas arch 2 gives rise to concha, antihelix and antitragus. The differentiation starts around the neck region but as the mandible develops the pinna structures move more cranially. It is not until the 12th week that the fusion of these various parts occur and is completed by week 20th.

<pubmed>17104502</pubmed>

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