In most instances the protruding ear is a congenital and/or hereditary deformity caused by maldevelopment of the anthelix. The angle between the concha and scapha is formed by the anthelix, and an absence or lack of development of the angle formed by the anthelix will result in a protrusion of the auricle away from the head. Since the angle of the anthelix determines the degree of protrusion of the ear, the pathology would resolve itself into the type and development of the anthelix, i.e., the more obtuse the angle, the more the ear projects.
Other pathological factors are encountered less frequently. A heavy concave concha will protrude the lower portion of the ear and is often accompanied by a thickened antitragus.
Congenital deformities of the helical rim are usually associated with a thin flat ear which may or may not be protruding but is frequently lopped forward at the upper