It is composed of a thin plate of yellow elastic cartilage, covered with integument, and connected to the surrounding parts by ligaments and muscles; and to the commencement of the ear canal by fibrous tissue.

Many mammals can move the pinna (with the auriculares muscles) in order to focus their hearing in a certain direction in much the same way that they can turn their eyes.

It has been suggested that during prenatal development in the womb, these muscles exert forces on the cartilage which in turn affects the shaping of the ear.

[7] Malformations of the external ear can be a consequence of hereditary disease, or exposure to environmental factors such as radiation, infection.

[19] This article incorporates text in the public domain from page 1033 of the 20th edition of Gray's Anatomy (1918) Media related to Outer ear at Wikimedia Commons