folding of antihelix (EFO_0007671, an Experimental Factor Ontology identifier) is any measurable or observable characteristic related to the shape and structure of the antihelix, a Y-shaped curved cartilaginous ridge arising from the antitragus and separating the concha, triangular fossa, and scapha. The antihelix represents a folding of the conchal cartilage and it usually has similar prominence to a well-developed helix. The stem (the part below the bifurcation) of the normal antihelix is gently curved and branches about two thirds of the way along its course to form the broad fold of the superior (posterior) antihelical crus, and the more sharply folded inferior (anterior) crus. The inferior and superior crura of the antihelix can vary both in volume and degree of folding.