The zygomatico-auricularis, which we look on as the homologue of the anterior auricular of man, draws the pinna of the ear forwards.
Temporo-auricularis Externus ([Fig. 92], 12).—This, which is thin and very broad, covers the temporal muscle.
It arises from the whole extent of the parietal crest, blending in this plane, in its posterior half, with the muscle of the opposite side. Thence it is directed outwards towards the pinna of the ear, and is inserted into the internal border of the scutiform cartilage and on the inner side of the concha—that is to say, of the conchinian cartilage—which forms the principal part of the pinna. We are supposing, in the description of the muscles which move it, that this pinna has its opening directed outwards.
The external temporo-auricular, which recalls, from its situation, the superior auricular of man, is an adductor of the ear; besides, it causes it to describe a movement of rotation from without inwards, so as to direct its opening forwards.
Scuto-auricularis Externus.—This muscle may be considered as supplementary to the external temporo-auricular; the concha fasciculus of this latter partly covers it.
Extending from the scutiform cartilage to the inner side of the concha, it contributes to the movement of rotation by which the opening of the pinna of the ear is directed forwards.
Cervico-auricular Muscles ([Fig. 92], 13).—These muscles, three in number, are situated behind the pinna of the ear; they are called, from their mode of superposition, the superficial, middle, and deep.
These arise, all three, from the superior cervical ligament, and pass from there towards the cartilage of the concha. They recall, as regards situation, the posterior auricular muscle of man.
Superficial Cervico-auricular (Cervico-auricularis superioris).—This muscle, inserted into the posterior surface of the concha, draws this cartilage backwards and downwards.
Middle Cervico-auricular (Cervico-auricularis medius).—Situated between the two other muscles of the same group, it proceeds, after having covered the superior extremity of the parotid gland, to be inserted into the external part of the base of the concha. It determines the rotation of this concha in such a way as to direct the opening of the ear backwards.