The concha and scapha form part of which human organ?

The most-striking differences between the human ear and the ears of other mammals are in the structure of the outermost part, the auricle. In humans the auricle is an almost rudimentary, usually immobile shell that lies close to the side of the head. It consists of a thin plate of yellow elastic cartilage covered by closely adherent skin.

The deepest depression, which leads directly to the external auditory canal, is called the concha (the "shell-shaped" structure of the cavity of the external ear). It is partly covered by two small projections, the tonguelike tragus in front and the antitragus behind. Above the tragus a prominent ridge, the helix, arises from the base of the concha and continues as a curved rim of the upper part of the auricle. An inner ridge, the antihelix, surrounds the concha.

The scapha is the groove on the outer ear that separates the the helix and antihelix.