Epigenetic regulation of the shape and position of the auricle in the rat.

We hypothesized that epigenetic (non-genomic) factors, related to muscular function, significantly regulate the shape and position of the auricular cartilage. We tested this experimentally by doing unilateral partial and total facial neurectomies, auricular myectomies, and ear rotations with skin excisions in rats. The neurectomies produced muscle atrophy, abolished the horizontal scaphoid ridging, and produced characteristic changes in the auricular shape. The myectomies of extrinsic auricular musculature alone were followed routinely by complete muscle regeneration and no changes in shape. The auricular rotations, with skin excision, produced an antihelix-like complex analogous to the human ear--a configuration that was permanent and was accompanied by muscle relocation. The findings are believed to support our hypothesis.