M. helicis ([Fig. 169], 3; [Fig. 64], m).—A muscle about two centimeters in length and five or six millimeters in width, on the inner surface of the ear, along its cranial margin.
Origin on the medial surface of the concha, just caudad of the proximal end of the tragus. The fibres pass distad to be inserted on the auricular cartilage at the caudal angle of the notch which lies beneath the cranial edge of the auricle, along with the caudal fibres of the adductor auris superior (1).
Relations.—Lateral surface with the integument; medial surface with the tragus.
Action.—Draws proximad the cranial margin of the auricle.
M. antitragicus ([Fig. 169], 6; [Fig. 64], n).—A small muscle about one centimeter in length and three millimeters in thickness, attached at one end to the caudal border of the antitragus. The fibres pass mediodistad and are inserted on the tragus, in common with the fibres of the tragicus medialis ([Fig. 169], 5, 5′).
Relations.—Outer surface with the adductor auris inferior and the integument; inner surface with the cartilage.
Action.—Constricts the external auditory opening.
M. tragicus medialis ([Fig. 169], 5, 5′).—A small, flat muscle, in two parts, on the medial surface of the concha.
Origin on the ventral end of the tragus. The cranial fibres form a thick nearly cylindrical bundle which extends proximad about one centimeter, and is inserted on the cranial surface of the concha just proximad of a deep fold in the cartilage. The caudal fibres form a thin sheet which spreads on the medial surface of the concha and is inserted on an obliquely proximodistal line on the medial surface of the concha, less than one centimeter from the free distal edge.
These two bundles are distinct except at their origin, and are sometimes considered as separate muscles.