Action.—Draws the external ear ventrad.
M. depressor conchæ ([Fig. 64], b).—A thin band of fibres, caudad of the last and parallel with it. The muscle arises as scattered fibres on the ventral surface of the neck, one or two centimeters craniad of the manubrium, the fibres of the muscles of opposite sides crossing the middle line and interdigitating. They pass dorsad, gathering together to form a narrow band which is inserted into the summit of the antitragus.
Relations.—Outer surface with the skin at the ventral end, and with the platysma (a′) further dorsad. Inner surface with the deep muscles of the neck and with the parotid gland.
Action.—Draws the external ear ventrad.
Lying deeper than the muscles thus far described, but closely connected with a number of them, are the following:
M. frontoscutularis. Origin ([Fig. 63], o) on the frontal bone, along the supraorbital margin, from the craniomedial angle of the eye caudad to the zygomatic process of the frontal.
The fibres form a large muscle which passes dorsocaudad to the scutiform cartilage and is mostly attached along its ventrolateral border. Some of the outer fibres, however, pass distad of the scutiform cartilage toward the cartilage of the ear, thus joining the adductor auris superior (f).
The outer surface of this muscle is closely connected with fibres of the intermedius scutulorum (a), the corrugatores supercilii medialis (b) and lateralis (d), and the frontoauricularis, when this exists. The outer surface is covered near the origin by the orbicularis oculi (c), farther dorsad by the muscles just mentioned and the integument. The inner surface is in relation with the frontal bone and the adductor auris inferior ([Fig. 64], o).
Action.—Pulls the ear craniad.
M. adductor auris inferior. ([Fig. 64], o.) (Part of the auricularis anterior of man.)—A small muscle lying beneath the frontoscutularis.