The facial muscles are evolutionarily descended from the gill arches in ancestral aquatic vertebrates, and this is seen during the development of the human embryo where five gill arches, called branchial arches, form initially, that later grow into more complex features. The facial muscles develop from the 2nd branchial arch, innervated by the 7th cranial nerve. This explains why Charles Bell named CN VII the "respiratory nerve of the face" (Bell, 1821). This respiratory origin of facial (mimetic) muscles might provide a compass to understand how the human face came to be.
