418 SENSE-ORGANS AND INTEGUMENT. 
integument which bears two longitudinal ridges projecting into 
the cavity of the ear, with a broad groove between them. 
The Scutiform Cartilage.—Closely connected with the 
external ear, but not forming a part of it, is the scutiform car- 
tilage. This lies in the temporal fossa, between the integu- 
ment and the temporal muscle, just behind the orbit and 
beneath the craniomedial portion of the auricle (Fig. 63, 1, 
page 97). It is a narrow cartilage about two centimeters 
long, with its long axis craniocaudal. For the greater part of 
its length it forms a slender rod, from which a thin cartilagi- 
nous sheet extends a short distance laterad; at its caudal end 
the rod forks, the two arms extending nearly at right angles 
‘to the main portion. The scutiform cartilage serves for the 
origin or insertion of a number of the muscles of the ear. 
Muscles of the External Ear (Fig. 169).—(a) The muscles 
connecting the cartilages of the external ear with other parts of 
the head have been described (page 96), excepting the tragicus 
lateralis (4). These muscles are the following: M. intermedius 
scutulorum (Fig. 63, 2), M. frontoauricularis, M. levator auris 
longus (including the cervicoauricular) (Fig. 63, g, 2”), 
M. auricularis superior (Fig. 63, 2), M. abductor auris longus 
(Fig. 63, ), M. abductor auris brevis (Fig. 63, 7), M. zygo- 
maticus (Fig. 64, @), M. submentalis (Fig. 64, c), M. depressor 
conche (Fig. 64, 4), M. frontoscutularis, M. adductor auris 
inferior (Fig. 63, 7), and M. tragicus lateralis (Fig. 169, 4). 
M. tragicus lateralis (Fig. 169, 4).—A band about seven 
millimeters wide, lying beneath the mass of fat about the ear 
and running ventrad lengthwise of the concha and close 
against it. 
Origin (Fig. 96, a, page 229) on the caudal end of the 
mandibula, in the cavity found between the condyloid process 
and the angular process. The muscle passes dorsad and is 
inserted (Fig. 169, 4) on the caudal margin of the tragus and 
in the depression on the concha just caudad of the tragus. 
Relations.—This muscle lies between the temporal muscle 
and the concha. 
Action.—Pulls the ear ventrad and probably rotates it 
outward. 
